Ισοκράτημα / Isokratema (Ison, Drone)
A comprehensive treatment of yet another controversial issue
Questions and Answers
What does the term "isokratema" mean?
D. Koubaroulis: Ison ("ίσον") of a musical Mode is - by definition - the pitch of its basis (tonic). For instance, the ison of Second Soft Chromatic Mode is the note DI. To hold ("κρατώ") the ison means to continuouly sing the pitch of the basis while the melody of a hymn is being chanted by the psaltis. The person "holding the ison" is called the isokratis ("ισοκράτης") [plural isokrates ("ισοκράτες") or isokratai ("ισοκράται")].

L. Angelopoulos: See his article, translated below, for a similar definition with more details.
What is the purpose of isokratema?
D. Koubaroulis:
a) To help the psalti learn and chant correct intervals. The co-sounding of the melody with the ison enhances the "idea" ["tin idea"] of the mode being chanted and helps the psalti apply the correct melodic attractions and intervals in general.
b) As a result of a) to help maintain the pitch of the basis of the mode throughout a (long) piece
c) As a result of a) to enhance the character of the mode being chanted and therefore contribute in transmiting the meanings of the melody the composer intended in places where modulation according to the meaning of the text takes place.
d) To enhance the beauty of chanting
e) To allow apprentice psaltai (and even non-psaltai) participate in chanting and learn by helping with holding the ison
f) To help cover up interval mistakes by the psaltis [Ref. Dimitrios Panagiotopoulos' theory book]

G. K. Michalakis: ...the most important, if not the only reason to have ison: To learn intervals and to chant correctly. Because in large churches, we have reverb.. Reverberation istself acts as ison, especially when using the "maradonna's foot" principle, where the most important notes of a passage are to be heard more than the rest. Once again we're into psycho-acoustics, whether you like it not ... for those chanting correct intervals, there can always be a slight dissonance on some occasions, where such notes are extended in durations (dissonant as to a previously emitted and continuously resonating note). One way to take care of this is to provide an ison, which will be in harmony with all the chanted notes: even an interval on plus one, (eg, Ni-Pa of Plagal Fourth mode) does *not* sound dissonant on an ison of Ni if Pa is chanted high enough, the way it's supposed to be chanted in psaltiki. All in all ison serves two purposes: Primarily (and most importantly) to help people learn correct intervals (this is so even in Hindu music) and, secondly, to cover up reverberating dissonances (and make things "sound nicer" as suggested above... when chanting in some non-resonating room, ison doesn't make things sound "any better"... it's just "extra noise". So, ison sounds better in some architectural context, namely that of a resonating volume.
What is the origin of isokratema practice?
S. Gugushvili: The origin of isokratema practice is unclear. Marcel Peres has speculated that it actually could originate in the West and was subsequently borrowed by the Byzantines: "There is some evidence that this practice might come not from the Greek but from the Latin…. The use of the ison seems to be known in the Byzantine tradition around the fifteenth century, but not in other Eastern churches. The first clear description of this technique, though, comes from a Western source, the Micrologus by Guido d’Arezzo in the eleventh century. For him it was a sort of organum. He teaches us that this practice was common in Rome. We know from the Ordines Romani that by the seventh and eighth centuries there were traditions of organum singing in the pontifical chapel. Later the anonymous author of Summa Music, a treatise written around 1200, describes the sort of organum that consists of a drone. He calls this manner diaphona basilica: that’s very interesting, because the term basilica in liturgical matters often refers to the Roman tradition. So in the thirteenth century there was still in the vocabulary of singers a word that seems to referred [sic] to the Roman Basilican tradition and that means a vocal drone. It is very possible that the Greeks borrowed this practice from the Italian singers. We find in some fifteenth- and sixteenth-century Greek sources, written in Byzantine notation, some instances of polyphony in this style with parallel fifths and contrary motion. In one manuscript a rubric says, “This is done in the Italian way.” We know that from the thirteenth century the Italians, chiefly the Venetians, had a very strong influence in some regions like Crete and Byzantium itself, where there existed a Latin government for almost seventy years. So there is a strong basis for this scenario."

The criticism of Peres' opinion as far as existence of drone in the West is concerned can be found in Robert Howe's master thesis, see pp. 6-8.

I. Moody: The article (actually a submission for a college degree) regarding this matter is quite a firm dismissal of the notion of the ison in Roman chant. The problem is that, in dismissing so summar ily the applicability of the terminology in this particular instance (and Peres's interpretation of the source), the author does not leave any room for the possibility of the ison being there at all. By coincidence, at the Colloquium on Mediaeval Monody currently being held in Lisbon and Evora, Professor Kenneth Levy gave today a very thought-provoking paper on the possibility of drones on Old Roman chant, based on a most exceptional neumatic occurence in a manuscript in London (BL Add. 29988). More is to be expected.

I. Arvanitis: "Diaphonia Basilica" is described in the treatise "Summa musice", written c. 1200. It is published with English translation by Christopher Page (Cambridge Univ. Press 1991): (p.124) : " Diaphonia is a manner of singing in two ways, and it is divided into 'basilica' and 'organica'. Basilica [diaphonia] is a manner of singing in two ways so that one singer continuously holds one note which is like a foundation melody for the other singer; his companion begins a chant either at the fifth or at the octave, sometimes ascending, sometimes descending, so that when he pauses he accords in some way with him who maintais the foundation" 'Organica' means contary motion of the voices. Summa musice mentions also "triphonia basilica", i.e. parallel fourths over a drone.
What is the (speculated) earliest evidence on isokratema?
S. Gugushvili: I collected a few things from Stathis' "Oi anagrammatismoi..." [tranlation to English pending]:

G. Stathis:
Page 31: Oi bastaktai einai oi isokratai safws anaferetai touto eniachou eis ta cheirographa, ws "oi bastaktai to ison", he "toutou psalletai meta bastaktwn" [1], he "psallei o domestikos meta twn bastaktwn" [2]. Ten psalwdesin tou kath' auto melous, twn bastaktwn isokratountwn he simpsallontwn, ten ektelei eite o choros - "apo chorou" he "oloi omou", eite o monophwnares kai kalophwnares (oroi oitines apantoun eis ta cheirographa3) meta enos he dio bastaktwn, eite prwtopsaltes he o lampadarios he o domestikos4.

1. Bl. Koutloumousiou 588 (b emisi IH ai.) f. 115r "Christophorou Mistakwnos, meta bastaktwn, echos a Oikos Israel - f. 122v Psalletai meta bastaktwn [kratema] - f. 123r O a meta twn bastaktwn [kratema]".
2. Bl. Iberwn 1120, f. 489r "Eita palin o domestikos meta twn sin autw, to Neagie, pl. d Neagie Doxa Patri", Katwterw, s. 36-37, ipos. 4. The ms Iberwn 1120 is by Manouel Chrysaphes the Old. Furthermore, on p.36-37, in footnote 4 we read: Bl. endeiktikws Koutloumousiou 588 (b imisi IH ai.), f. 115r "Christophorou Mistakwnos, meta bastaktwn, echos a Oikos Israel - f. 122v Psalletai meta bastaktwn [kratema] - f. 123r O a meta twn bastaktwn [kratema]". Allai martiriai, ek twn pollwn, Koutloumousiou 455 (ai. IE-IST), f. 12v "Prologos meta isou, tou Chrysaphe [Manouel], echos d Ererrere" - Koutloumousiou 457 (ai. ID, b imisi), f. 6r "Entautha archetai o dexios choros, isa kai arga, oi oloi omou pl. d Panta en sophia" - f. 104 v. "Eita echizei o domestikos kai psallousi exo oloi touto, outws arga kai isa [echos] b Doxa en ypsistois Thew kai epi ges eirene [kalophwnikon] - Docheiariou 379 (a emisi IZ ai.) "Eirmoi kalophwnikoi, entechnoi... psallontai arga kai isa". Eis tas periptwseis autas kai tas paromoias paratiroumen eukolws oti he anagke tou isou tonizetai eis mele kalophwnika, ta opoia prepei aparaitetws na psallwntai kai argws, he malista "argws kai meta melous". Edw fainatai oti sticheion organikon tou melous einai to ison. .... Peri bastaktwn, arkountws diasafetike einai he martyria tou kwdikos Iberwn 973 (IE ai. archai) f. 16r. "O domestikos apo chorou, meta twn bastaktwn autou, oion anagnostwn kai loipou laou autou, echos pl. a Idou de eulogeite". Diafainetai en te martyria taute oti oi bastaktai pros tois allois ergon eichon to isokratema.
When was isokratema first written down?
D. Koubaroulis: Georgios Lesvios was the first to write the isokratema down in 1847 according, as he claims, to the tradition of Constantinople of the Great Church (see L. Angelopoulos' article below for more details).
When was isokratema first written down in the New Method scores?
S. Gugushvili: According to Dimitri Giannelos' theoretikon "La musique Byzantine" prior to 1950s isokratema indications were rare. One encounters it e.g. in Monk Nektarios' "Mousikos thesauros tes leitourgias", vol. 2, p. 631 ff.
Is there evidence that isokratema existed after the Byzantine times and before 1847 (when it was first written down)?
D. Koubaroulis: Yes. Two respected sources mention it.

(Translated by D. Koubaroulis).
Apostolos Konstas , Book Title: "Apostolos Konstas o Chios and his contribution to the theory of the Music Art" Author: Thomas Apostolopoulos Editor Gr. Stathis, Atena, 2002, ISBN 960-86798-1-8, 364 p., 30x173x241mm (Details at http://www.csbi.ro/gb/recenzii.html) I quote: The well known theoretician Apostolos Konstas o Chios, writes in his theory book (ms EBE 1867) in 1800 AD: "... the ison of every mathema which is held by the isokrates is found (as with) all the isons of the modes between the authentic First mode and its low Heptaphonia (octave) the so called asiran". from the original Greek "to de ison kathe mathematos opou vasta o Isokraths euriskontai apanta ta isa twn hxwn apo ton kyrion hxon prwton, mexri tin katw eptafwnia autou, to legomeno asiran".

So not only we have evidence of an isokratis "holding the ison", but also evidence that indeed the ison that is held should correspond to the ison of the mode i.e. the basis of the mode at any time.

(Translated by D. Koubaroulis).
Basileios Stephanidis (1819, but writing a theory book on the Old Method), Book Title: "Sxediasma Peri Mousikis kai malista Ekklisiastikis", published with commentary by Halambos Karakatsanis [details pending]. He says in paragraph 79: "In any case, it is certain that the melody can sound nice and pleasing to the ear even when that octave harmony is not there because the whole art of harmony consists of this: to hear notes ("fthoggous") together with those of lower pitch or with the ison of the melody ("h me to ison ths melodias") and whether these (dk: lower pitch?) notes are in the same scale/octave? ("eis thn idian diapaswn") or in another harmonic one ("h eis allhn symfwnon") there is no difference ("oligh h diafora").

S. Gugushvili: We also have a Western source talking about chanting with drone (isokratema) in the 16th. c. Constantinople: Martin Crusius in his "Turcograeciae libri octo" (Basel, 1584) mentions reports of people who heard the drone sound.
What is the earliest written down theory on isokratema?
D. Koubaroulis: The earlier (somewhat brief) theory on isokratema is the one mentioned by Apostolos Konstas (see reference above) where he says that the isokratis holds the basis of the mode being chanted. After that, Father Charalambos Oikonomou gives a description of how isokratema should be done:

(Translated by D. Koubaroulis).
Father Charalambos Oikonomou from Cyprus wrote in his book "Byzantines Mousikes Chorde" in 1940 (paragraph 207): "So when the basis of the mode moves to a higher or lower dominant note or changes to another genre or system, doing cadences, the isokratis brings thes ison there, preferrably in the lower octave; isokratema in the high octave ("diapason") is not allowed. The isokrates co-chants with the psalti saying the syllables of the text with him and many times by a sign of the psaltis joins him in the intermediate or final cadences or he himself (the isokrates) does the cadences. During a chant, where the psalti may stop to breath, the isokrates is not allowed to disrupt the ison but he should change it to humming and resume it when the psalti continues the melody"

There is also an analysis of isokratema in the theory book of Dimitrios Panagiotopoulos. [pending]
What did Stylianos Tsolakidis (expressing Patriarchal practice at the time of Iakovos Nafpliotis) have to say about ison?
G. K. Michalakis: : [My teacher] Tsolakidis said "ena einai to ison". In slow pieces, whether the melody ascends or descends, the ison remains the same, fixed on the basis and does not move. The canonarchs [of the Patriarchate] were allowed to change ison on some occasions, in general by triphonia (fourth) or tetraphonia (fifth), ver rarely diphonia (third). Those who were not initiated would keep the same ison, which suggests that there might have been a form of double ison in the Patriarcheion. In fast pieces (canon), the ison would involve the known "M" for "mazi" or "melody", meaning that in the descending, below the ison part, the isocrate would sing along. In slow pieces, things are bit more complicated. Recall, there were Isokratis, Domestichos, Canonarchos, etc... The first canonarchos was the only one allowed to do what the the "boithos" =helper Domestichos would do: sing along the various conclusion cadences. The first Domestichos would sing along almost 100%, except for difficult passages. My conclusions are the following: The patriarchal choirs were never 100% complete, for at Iakovos' time, there was lack of personnel. But imagine we have 10 isokratis, 3 canonarchos of which the first (for one octave higher voices), 2 helper domestichos and the first.. what can we do? We may do double ison, but the second, non basis ison will be much more disecreet than what is done by EBX... the "entrance" and "exit" is done with "progressive changes of intensity", and the overall volume of a second ison is only about 30 to 60% of that of the basis ... it is discreet.

I add here what I had said elsewhere: when the number of chanters is limited to 2, the one doing "ison" can do almost any other function: that of domestichos, canonarchos, ison, etc. In this case, when the melody "changes" to some new principal note (fthongos) the isokratis can change so as to "help" the teacher. This is the method that has remained in the "Patrarchal" ison of today, and which Stanitsas, and later on Vassilikos pushed to "extreme" = never-ending ison changes. When the choir was in complete form, the Protos canonarchos would change his recitation to the chord of the melodic line (for instance: in "ton pathon", ison is on Ni... the melody goes to Ga.. the Canonrchos does so, at "ta panta prosietai", and then comes back down to Ni for "tois prowkynousin en potho..). In choral form, the ison would stay on NI, in spite of the canonarchos' change of pitch. Yet, the canonarchos would do his ison at his pitch of recitation. This gives us a form of "double ison". In none of these situations does the canonarchos do a recitation on Pa or on Di = Pa (that is, he does not use a "dissonant" interval as to the basis, Ni in the first case, Ga in the second).

Now, when chanting alone with the teacher, on lines of plagal fourth concluding on PA , or on Di = Pa, Tsolakidis would change his ison. He explained to me that when the choirs were at their fullest "Pascha, Acathistos", they'd apply the above- mentioned "isokratima" tactics. On other days (about 95% of the situations), the Protocanarchos would learn to change just as modern Stantisas-type of choirs in very limited manner... for instance, a simple Pa on plagal fourth, with no Low Di, no Bou, ... in other words, the only other ison allowed, except for tri/tetraphonia of the canonarch's recitation, was the dissonant (as to the main ison) fthongos, with no double ison (the canonarch's recitation was also the ison). eg: Idou o Nymphios argon: Recitation on Ga = Ni... changes to Pa for "alla ananipson krazousa". Just about when started learning the neumes, he had to learn by heart where to change the recitation for Iakovos. And here, we add the other very important purpose of ison: it's an integration element = it is used to initiate novices to psaltiki, so that they may progressively "blend in" and participate.

"Ena einai to ison" does not come just from Tsolakidis, but from Iakovos... he would teach him to "change" ison in one or two places (and he even told me when Iakovos told him this... =when they were studying "ton Agion Pateron"), all in saying "kanonika, ena einai to ison" normally, one is the ison. the variable ison in a few positions, by the entire choir, and especially as concerns dissonant note as to the original ison is really to be considred as a concession. When he chanted "ton Nymphona sou", "makarios anir", etc, he would ask me to keep tha same ison, and not even to "chant along the lower than ison fthongos". Is pieces such as fourth stichiraric, ison = bou, and [co-chanting] "mazi" for descending lines. Quite honestly, this is one mode where it's hard to keep a constant Bou... the isokratis was always in advance on coming back to the BOU (the psaltis would not have to "imagine it), before the psaltis would go on chanting. third mode always GA, even if the melody would go beyond Ke.. or below Ga
What does Lykourgos Angelopoulos (expressing the views of Simon Karas and his own research) have to say about isokratema?
Angelopoulos has written a very informative article on the subject [html] (in Greek).

D. Koubaroulis : I didn't have much time to do the translation so I am sure there are mistakes. I found the article interesting and informative but I have to mention my surprise that Angelopoulos does not refer to Apostolos Konstas when he talks about isokratema. Dimitrios Panagiotopoulos also mentions double isokratema and I don't think he was influenced by Karas. He is not mentioned either in the article. Finally the article seems to condemn modern practice on isokratema altogether and propose Karas' views as a sound alternative. There is no mention to the Patriarchal or Athonite practice at all. Also no mention on whether some pieces don't really need isokratema at all (despite the fact that he presents evidence from the Byzantine times supporting this claim).

by L. A. Angelopoulos (director of the Greek Byzantine Choir)
translated by D. Koubaroulis

The term "isokratema" in Byzantine Music means the continuous horizontal co-sounding of the tonic of a mode or -more precisely- the tonic of a tetrachord or a pentachord with the melodic line. The word is composite: "ison" and "kratema". Sometimes we see only the word "ison" which means exactly the same thing, the "kratema" or "holding" of the ison. In music, ison is the first and only sign of Byzantine notation that is characterised as "the beginning, middle and system of all signs of the Psaltic Art. Without ison, there is no voice ("fwnh" = melody?). Ison is called "aphonon" (lit. mute) not because there isn't any melody associated with it. Ison can be counted ("metreitai") but not voiced ("fwneitai"). And depending on the amount of equal notes, the ison is chanted". That is found in all the prefaces of the theories of the old-method Papadike. From there it is, I think, that the etymology and literal meaning of the term "ison" derives: the continuous vocal repetition of the appropriate note each time, which note is called "ison", is the so called "holding of the ison" that is, the "isokratema".

It is well known that the musical system of Byzantine chant is monophonic, modal, purely vocal, written-down, with well known composers and compositions that are artistic and complete musical works even though they are intended almos exclusively for liturgical practice in Church - which of course is the centre of the Christian's life. However, there are also compositions that can be chanted outside the Church like, for instance, "at the table" which nonetheless is a continuation of liturgical congregation. Written tradition is interpreted by oral tradition and complemented by it. The microtonal variety and the effects of the signs are core elements of a complete interpretation. The isokratema, witnessed from the Byzantine times in manuscripts either with the mention of the name of the person that does it ("vastaktes" = holder/supporter) or with the definition of the job of a "vastaktes". Having observed the above terminology in some compositions of manuscripts, I could conclude that not all pieces were changed with "vastaktes" but only those that explicitly said so. Equivalent to the "vastaktai" of the East in Western musical practice are: the four last members (out of the seven) of Scuola Cantorum, that is the archparaphonist and the three paraphonists (the first three members are the primicirius, secondarius and tertius). So much with the evidence of "vastaktai" (holders) of ison in the Byzantine period because, in my knowledge, there is no evidence of written isokratema in composition, in Byzantine as well as in the post-Byzantine period.

After the introduction of the new method of the 3 teachers (beginning of the 19th cent) the first evidence of written isokratema in books dates around the beginning of the 20th century. It is quite surprising that the first notated isokratema in the 19th century is not found in books of the New Method (of the 3 teachers) but in those of another method called the "Lesvios' system" (a system that was justifiably rejected by the Ecumenical Patriarchate because it destroyed irreversibly the link between the practiced method and the older methods of the centuries-old musical system).

A parenthesis: The huge importance of the connecting link between the older systems and the currently practiced one was pointed out and demonstrated first by Simon Karas with the identification of the effect of certain signs with oral (as well as written) tradition. Later research proves gloriously ("panygerika") the correctness and necessity of the views of Karas - let me mention the extremely well documented doctoral thesis of Georgios Konstantinou that was approved last year by the Ionian University. End of parenthesis. So the first notated isokratema in the 19th century happens by Georgios Lesvios in the book "Meliphonos Terpsinoe" a two-volume anthology published in Athens in 1847. The texts were "converted" as interpreted by Georgios Lesvios from the method of the 3 teachers, to his own method. In the preface of that work, Lesvios notes: "In the most well known pieces of the second volume, we added the signs of change of the bases (or the isa) which should co-chant softly ("ta opoia thelousi ypadein ypechountes (isokratwsi)" the "isokratai" while the piece is chanted as is observed by those chanting n Constantinople and indeed in the Great Church. However, they (dk: the isokratai) should also be musicians otherwise they can make mistakes". The phrase here "as it happens" creates some doubts as to whether Lesvios heard and wrote the isokratemata exactly as they were done in the Great church or that he notated them following in general and "approximately" the standards and the tradition of the Great Church. Both assiptions are equally possible. The observation of this first evidence of written down isokratema is due to philologist M. Xatziyakoumis and took place while cataloguing the printed music books.

I will not go into details regarding this notated isokratema as I have already given my texts to musicologist Sotirios K. Despotis, PhD candidate at the University of Vienna, who dealt in detail with the subject (for more information see his final year dissertation at the Ionian University titled "The application of the co-sounding ("synechetikou") system of Byzantine Ecclesiastical Music in Byzantine Ecclesiastical Melos through Theory and Practice of the 20th century", Corfu, 2002 and in a paper by the same author in the international conference of Vienna University (3-5 Oct. 2002): "Die Isokratema Praxis der Byzantinischen Kirchnmusik"). In 1902, the Protopsaltis of Smyrna, Misael Misaelidis publishes his "Neon Theoretikon" consisting of 3 parts: 1) About our Ecclesiastical music 2) About Ancient Greek Music and 3) Various Ecclesiastical Hymns etc. In the third part and from page 63 onwards, where the per-mode Cherouvika start, a capital I is written on the notes that the isokrates should change the ison. Much later, in 1924, Stylianos Hourmouzios of Cyprus will use the same method (capital I) with the same meaning in his book "Ecclesiastical Salpingx", vol. 3, Liturgy.

In the years of activity of the Patriarchal Committee of 1881-1883 we can identify a trend to seek a more systematic manner of co-sounding of the melodic line and the isokratema. Central figure in that attempt is the Fanariot (Constantinopolitan) Archimandirte Germanos Afthonidis, president of the Commitee. A very interesting piece of information that involves Germanos was kindly offered by Protopsaltis and researcher Konstantinos Markos. In a text by well known French musician L. Bourgault-Ducoudray, the translation of which will be published by K. Markos soon, it is mentioned that Ducoudray had repeatedly met and discussed with Afthonidis on the possibility of some kind of co-sounding support for the melodic line. Ducoudray suggested some solutions but without success because Germanos would not accept them. In the end, the French musician suggested to Germanos two co-sounding lines (deux harmonisations) which Germanos accepted and they named them due to their primitive simplicity (vu leur simplicite primitive) as "diplo ison" ("double ison"). I do not have any more information on the fate of that work but quite possibly that could have been the inspiration of the double supporting or co-sounding line promoted by K. Psaxos when he came to Athens from Constantinople, as the first teacher of the newly founded School of Byzantine Ecclesiastical Music of the Athens Conservatory (1904) .

On Psahos' double co-sounding line we observe the following: 1. He doubles parts of the melody in unison or an octave apart which results in the ison to lie in the middle and the melody to move higher or lower than the ison. When the second voice moves, the third is holding the ison and vice-versa, when the third voice moves, the ison is done by the second voice. 2. In this case the two voices chant together (in unison) while the third holds the ison 3. All three voices chant in unison, without isokratema. The above cases are observed in both syllabic and melismatic pieces. In particular, the melismatic pieces differ in the melodic lines that are suitable for solo ("kalofwnia"). In such a case, the ison is held by the second or third voice in unison or as double ison (dk: two different notes). The in-depth study of the system of the 8 modes as well as the effects of the notation signs, led Simon Karas to build a teaching that gives clear, complete and justified answers to the issue at hand. In general, I could say that in the first half of the 20th century, the trend for some kind of enrichment of the isokratema, in order to counter the increasing popularity of Western polyphony, is quite strong. And Simon Karas himself goes a long way in a short period of time, from the first recording of 1930 (by Melpo Merlie) until the formation of his teaching on isokratema, on the basis of the system of the modes and the effects of the signs of the notation. The operation of "double isokratema", as he names it, is different from the co-sounding line ("synhxhtikh grammh") of Psaxos. Double isokratema of Simon Karas exists when there are common notes when moving from one mode to another inside a piece, with adjacent ("synhmmena") tetrachord (e.g. in cases of moving from low First Mode or Plagal Second Mode to Papadic Fourth Mode Agia). Whichever change of the isokratema has to follow the musical phrase from the beginning, something which often is not so clearly visible and easy. Especially in cases where a musical phrase can belong to more than one mode, depending on how it is chanted, applying the characteristic elements of this or the other mode. The structure of the pieces plays an important role as to the placement of the isokratema. In his "Theoretikon", S. Karas has a detailed teaching on the isokratemata of all modes for someone who wants to read more on this subject.

Modern psaltic practice appears contradicting with respect to isokratema. On one hand there is a will for study, research and to follow all the rules of our musical system. On the other hand, one can see a carelessness ("proxeirothta") and adapting to the existing dead-end practices of education and knowledge. The worst is the view of isokratema using the logic of Western music and of vertical harmony which has absolutely no relation to our musical system. And even worse, the influence of such logic at the practical level, in cases where there is no knowledge of Western music but a modern aesthetic understanding which gets infuenced by Western and/or Eastern sources and remains captive to manufactured sounds ("typopoihmena akousmata") that do not take into account neither the modal system nor the effects of the notation signs. The in-depth study, complete knowledge of the structure and operation of the system of the Octoechos (8 modes) as well as the effects of the notation signs is required for a justified documentation of isokratema.

L. A. Angelopoulos Archon Protopsaltis of the Holy Archdiocese of Constantinople Teacher of Byzantine Music at the Filippos Nakas Conservatory, Athens
Is isokratema an influence from secular (folk) music?
D. Koubaroulis: No. Isokratema is not a characteristic of secular (folk) music.
Who introduced double isokratema in Ecclesiastical music?
D. Koubaroulis: In practice, it is believed that some form of double isokratema has always been evident in psaltiki in the case where there are many isokratai as witnessed by the Stylianos Tsolakidis in the Patriarchate (see comments by G. K. Michalakis: above). Lykourgos Angelopoulos traces the origins of systematically taught double isokratema to Western influences and identifies Germanos Afthonidis, the president of the Patriarchal Committee of 1881 as the one who introduced it (see his article above).

John van der Hoek: Evthimiadis regularly uses double isons in his books [eg three volume book ''Ymnologion Phonais Aisiais'']. He has a chapter on Isokratemata [Chapter K', pages 463-484] where he also demonstates double isons. {this refers to the 3rd edition, 1988]

What about the controversy regarding the appropriate ison of Second Soft Chromatic mode?
See special page on this [html].
What is the commonly accepted traditional theory on how isokratema should be done?
D. Koubaroulis: In theory, it is that ison should be kept on the basis of the mode or at least the tetrachord/pentachord of the melody being chanted. In practice, there is no commonly accepted theory. See schools of thought below.
Why don't the three teachers and other theoreticians say anything about isokratema?
D. Koubaroulis: Perhaps because it was assumed well known at that time. But really, I don't have a good explanation here.
What should the relative volume of isokratema should be compared to melos?
G. K. Michalakis: Discreet. It should also vary in intensity, giving an additional puslation to the melody according to the text (not the music..). It's this varialbe intensity of the ison that draws attention to a particular word (example... "zoopoio" in the Cherubikon.

D. Koubaroulis: I agree, ison should be discreet. Supporting and not competing in volume with the melody. Good examples are the recordings of Fr. Dositheos.
Who introduced frequently changing isokratema in modern practice?
D. Koubaroulis: It was an influence of the intrusion of Western polyphony in Orthodox churches during early 20th century and the development of the first "Byzantine" choirs such as that of Simon Karas (Melpo Merlier recordings ~1930), Konstantinos Psahos and others.

G. K. Michalakis: Modern technical brains, who like to dissect psaltiki. They ended up Westernising it (in philosophy, in intervals, in sentimentalism...)
When should isokratema start and stop?
D. Koubaroulis: No hard and fast rules. I follow the practice of L. Angelopoulos, starting the isokratema on the last note of the apechema and ending it at the end of the melody together with the psaltis. Isokratema may stop at cadences if there is one isokratis and needs to catch his breath. In other times, isokratema may stop between parts of a piece e.g. between the main piece and its associated kratema etc.

T. Nassis: Closer attention to the expertise of the EBX will show that within slower, papadic melodies all the isokrates may need to break and take a breath if they need to. For example, at the their successful Nov 2005 concert in Boston, the entire choir broke before and after the te-ri-rem of the koinonikon "Lytrosin Apestelai." Isokrates are not robots, and need to be respected as artists in their own right.

Should the isokratema be stopped at cadences?
D. Koubaroulis: Further to the answer of the previous question, it happens quite often in modern studio and concert recordings of choirs like the one of Thrasyvoulos Stanitsas. The usual argument is that the isokrates need to catch their breaths and rest especially in long pieces. Other more conservative choirs (like the Greek Byzantine Choir) do not generally stop the isokratema at cadences. It seems to be a matter of taste. I prefer continuous isokratema at the cadences to avoid the "hiccups" sound produced by stopping isokratema and melody together, especially when done too abruptly as experienced by a few modern choirs.
Should the priest's ekphoneses be accompanied by isokratema?
D. Koubaroulis: No. Ekphoneses are not hymns even though some priests unfortunately extend them to elaborate melodies to which the psaltai hold ison from their places. When a priest (or bishop) is chanting a hymn then isokratema can be held for them by the isokrates.
How many isokratai should there be at different occasions?
D. Koubaroulis: There is no rule here as long as the principles of isokratema apply. See the next question.
Can there be more isokratai than psaltai in a choir?
D. Koubaroulis: Yes, though unusual and uncommon. In general, more isokratai makes their job easier and results in an uninterrupted sound when they breath at different times each. However, the principle of ison sounding much softer and discreet relative to the melody should apply.
Some modern protopsaltai appear in concerts as soloists supported by more than one isokratai. Is that traditional?
D. Koubaroulis: They do it for isokratema to be richer and uninterrupted while the isokratai stop to breath. As long as the isokratema volume is much lower than the melody there is no problem with that.
What sound should the isokrates use for isokratema?
D. Koubaroulis: [pending]

G. K. Michalakis:
Base (3 psaltis)(one octave below): o -a blend, all the time (no consonant pronunciation, no change in vowels that do not last a long time)
basis 1 (5 psaltis) same as above; they vary intensity according to text
basis 2 (2 psaltis) they pronounce the consonants and the vowels, but they should be very discreet - they should not vary intensity according to word (the consonants will alter the entire melody = military, as Zoe...)
tetra/penta chord 2nd ison (2 psaltis), discreet, o -a blend, all the time (no consonant pronunciation, no change in vowels that do not last a long time) they vary intensity according to text
What are traditional examples of isokratema in recordings?
D. Koubaroulis: Many live recordings (e.g. from the Patriarchate and Mt Athos), Fr. Dositheos recordings, Manolis Hatziyakoumis CD series, the Greek Byzantine Choir and its followers and others.

T. Nassis: ...the "Eksedysan Me" of Priggos that Panagiotis Koutras chants as a solo on the EBX CD "Byzantine Hymns" (Benaki Museum of The Velimezis Collection Project) is a wonderful example of amazing isokratima that defies any simple "recipe" of what makes good isokratima.

What are non-traditional examples of isokratema in recordings?
G. K. Michalakis: Stanitsas, Zoe (choir), Vassilikos (in increasing order of deviation)

D. Koubaroulis: Here is a non-traditional example of vertically harmonised apechema of "Nenano" by Pavlos Fortomas's choir [pending]
Who introduced mechanical (synthesized) isokratema in recordings and is it allowed?
D. Koubaroulis: The earliest recordings we have with synthesized isokratema are from the CD "Music of the Greek Orthodox Church 1924-1930" published by FM Records in Greece. Listen to the recordings by Petros Maneas and Konstantinos Thomaidis for instance.
Who introduced mechanical (synthesized) isokratema in Church services and is it allowed?
D. Koubaroulis: The first mechanical isokratis designed for use in Church was developed by Georgios Naoum, a well known psaltis from Athens. Since the, others have also constructed such machines. Theodoros Vasilikos is the most well known protopsaltis that uses such a machine in the service. Many traditional psaltai and Bishops have condemned the use of mechanical isokratema in church and as a result its spread is very limited.
What is the role of the isokratis (the person that "holds" the ison)?
G. K. Michalakis: First, to participate, second to learn and third, to "help out"...

D. Koubaroulis: I agree. Where "helping out" means to help fulfil the purposes of isokratema mentioned earlier.
Does the existence of isokratema contradict the claim that Psaltiki is monophonic?
D. Koubaroulis: [pending]

G. K. Michalakis: No... because one needs to have a unique, steady ison to learn intervals correctly. Once learnt, these intervals can be chanted with or without ison. It's the overall "acoustics" that will determine the necessity of its use in actual sevices.
Should the isokratema be written down at all?
G. K. Michalakis: Never... using notes is mechanical enough. adding bar lines and ison is a nice way of turning people into robots.

D. Koubaroulis: It is useful in teaching and learning. However, once someone is experienced enough they do not need to have isokratema notated to perform it correctly. This is, in my opinion, the reason why the classical books do not have isokratema notated.
Can the congregation participate in chanting by doing isokratema?
G. K. Michalakis: That would be a dream come true...

D. Koubaroulis: It often happens especially in well known pieces and especially when (non-psaltai) people standing around the analogion feel musical enough to join in. I very much like it and encourage it.
Why don't most classical books of the 19th century notate isokratema?
G. K. Michalakis: Why don't they annotate so many other things, as well.

D. Koubaroulis: See earlier answers. There is no need to notate the isokratema in Church books other than for teaching purposes.
Why isokratema is not heard consistently in Patriarchal services?
G. K. Michalakis: If they're losing chronos, it's natural that there are less people interested in chanting some constant note... (this is just an additional factor to the continuously diminishing Greek population of Constantinople)...

D. Koubaroulis: I would also attribute it to the diminishing population and the attention shift to "save as much as we can" which does not include ison (perhaps as something not as vital as other elements of practice).
What are the different schools of thought regarding isokratema?
D. Koubaroulis: It'd be good to establish category names for the different types of ison schools:
- basic ison (=only the basis of the mode)
- conservative ison (=tetrachords/pentachord and mode changes only)
- moving ison (=conservative ison + some vertical harmonisation similar to Stanitsas's scores)
- westernised ison (=vertically harmonised ison)

When double ison is used one could say "double conservative ison" or "double moving ison". Are there more categories? Any better names for the categories above?

G. K. Michalakis: We just read them above (L. Angelopoulos' article).
double: unique, continuous ison, with added secondary ison on triphony and tetraphony.
single with conservative changes, with anticipation on dissonant notes (as compared to the mode's basis)
single, with "generous" ison changes (Stanitsas/Vassilikos/Zoe): from left to right, their intervals start changing, and I suggest that this is so because of the changing ison, (from the psaltic to the Western tempered scale). Classical examples are the "diatonic KE" becoming lower, the Bou higher, and, of course, the Pa lower. Changing from GA to Ke on third mode has completely abolished the beautiful pitches of DI, KE, Zo, Ni PA of third mode, bringing them all down.
multiple (Psachos) triphonic (add to that the organ of American churches), with occidental intervals polyphonic (tetraphonic) = slavonic style.

I don't find it hard to imagine that perhaps there were chants back then that would sound as beautiful as Georgian or even Corsica harmonisations using PSALTIC intervals. I don't feel that polyphony could not have existed... it could not have existed with Western and Simonokaraitic intervals. But once Kyriakos Tsiappoutas will give us all of the Iakovos intervals, I will try to harmonise some piece using melodos... and I think that the result will be amazing...
What is the "synechetike gramme" (co-sounding line) proposed by Konstantinos Psahos to harmonise Byzantine Chant maintaining the Byzantine intervals?
See L. Angelopoulos' article above.
Is isokratema "easy" and "cheap" (as once heard) and should it be left to untrained psaltai?
D. Koubaroulis: No it is not easy. To do it properly it requires musicality, knowledge of the music and the text being chanted, psaltic experience,and good aesthetic criterion. It requires vocal and breathing stamina and very good pitch. Untrained psaltai can do isokratema as long as there is someone to guide them as to when and where to they should change.

T. Nassis: Any serious and talented chanter and isokrati will tell that there are many tricks to the trade of performing great isokratima. To believe like some that isokratima is easy just isn't true. (I was embarassed to hear Taliadoro arrogantly say to his isokrates in my very presence, "To isokratima einai ftino.") The 'secrets' are many.

S. Herron: I, having to teach and chant in America where trained chanters are a large deficiency, am much in favor of having untrained psaltis hold isokratima and my reasons personally are VERY practical: 1) It gives the "students" something to do, 2) it forces them to pay attention to what is being chanted and they become more interested and listen to the piece and I believe retain more of the piece and tone 3) and on a very practical level it keeps them interested and feel like they are contributing when they are not advanced enough to actually chant themselves. Unfortunately, many would lose interest if I made them stand there and listen. Now while it may be different in places with highly trained chanters like the Patriarchate or Agia Eirini (despite the many criticisms of the style, the chanters have by all means been schooled very well on the Karas method there) or anywhere else with a high quantity of chanters, but I see no problem in having beginners or untrained psaltis hold isokratima, in fact, I think it is something where it will be spiritually beneficial to them and practically beneficial in learning the music.

How should isokratema be notated (when it is notated)?
D. Koubaroulis: It is better to be done discreetely avoiding fancy colours, bold letters and circles and preferably in black or red ink (which is more consistent with manuscript tradition). Good examples of notating isokratema are the scores of the Greek Byzantine Choir.
How should isokrates train to do their job?
D. Koubaroulis: Initially, in teaching, they should be presented with scores with notated isokratema. In Church, there should be a master isokratis responsible for the trainees and help them with when and how should change the ison everytime the mode chanted changes. The psaltis should supervise and correct the performance of the isokrates at all times.
Should all chanted pieces (even the simplest ones) be accompanied by isokratema?
D. Koubaroulis: No. Not necessarily. [Details pending]
Should ison change to NH in First mode cadences?
G. K. Michalakis: No.

D. Koubaroulis: No.
Can ison ever be held higher than the pitch of the last note of a cadence?
G. K. Michalakis: Yes

D. Koubaroulis: Yes. For example DI of Second Soft Chromatic mode on some cadences on BOY.
Should the apechema be accompanied by ison?
G. K. Michalakis: Why, then, call it apechema ("outside" or "derivative" of...echos = melody)

D. Koubaroulis: Lykourgos Angelopoulos says no (as it contradicts the main reason of the apechema which is exactly to provide the pitch of the ison to the isokratai), except for the last note of the apechema which is the actual note to be help by the isokrates and on which note isokratema starts, blending the apechema and the main piece and preparing the melody to start shortly after. I personally like and encourage this practice.
Can ison change for the duration of a single note only e.g. like in temporary cadences in BOY in Plagal First mode?
G. K. Michalakis: No

D. Koubaroulis: Most psaltai do change the ison in cases where they think that the mode temporarily changes even on one single note and usually to avoid dissonance resulting in a form of vertical harmonisation. If ison is held discreetly one should not have to change in such cases and the dissonance is not noticable or adds some "surprise" element to the experience of the listener.

What is the right isokratema when the melody stops and rests in BOY of Plagal First mode?

G. K. Michalakis: PA.... BOY should be in it's psaltic position (yet, we add as "diesis reminder" which psycho-acoustically is treated as =push up the BOY... but the BOY is where it should be... with no "push", it may become slightly low and dissonant).

D. Koubaroulis: Practice varies. PA seems like the most traditional choice there. Well known choirs like the Greek Byzantine Choir do a low KE (reasons pending) and the Maistores do BOY (joining melos). [More details and examples pending]
What does "vertically harmonised" isokratema mean?
See L. Angelopoulos' article above.
Can children do isokratema (at one octave higher than the basis of the mode i.e. despite the rule that ison needs to be lower than the melody)?
G. K. Michalakis: Of course... half the isokrates in Tsolakidis's time were the "schmunks", "bambinos".

D. Koubaroulis: As mentioned in other questions above too, ison helps children participate, learn and help the psaltis.
Why did Nafpliotis, Pringos, Stanitsas (in Constantinople) and Dositheos recorded many or all of their material without isokratema?
G. K. Michalakis: Because they knew their intervals inside out... Especially Iakovos. Ison has helped me "place my voice" when I forget. But for pieces I know "inside out", I've started recording without ison... I add an ison later (before, I'd most often use the ison even during recordings, although it is not heard in the recordings). I don't know why yet, but the end result is better without the simultneous ison (only for pieces i know... for pieces I don't know, the ison helps me determine an overall "balance " among the various pitches. The ison helps one to obtain "natural, psaltic intervals".

D. Koubaroulis: We do not know with certainty why they didn't use isokratema, We can only guess. Possible explanations:
a) They thought that ison was not needed once they had learnt good intervals, not caring about its "beautifying" role or its actual use in Church practice
b) Their isokrates were trained to do ison ad hoc which would not sound well in a studio recording where a systematic approach would be required for a "professionally uniform" performance.
c) The recording technology did not support many people chanting together (?)
d) They wanted to show that ison "does not formally exist" in Church recordings and is only used for learning (although that contradicts the claim that some of those recordings were "paedagogical")
e) The recordings were done informally or "on the spot" and there was no time to find trained isokrates
f) They wanted to showcase their performance as clearly as possibly, not mixed with (possibly occasionaly out of tune) isokratema

Or (my personal take) a mixture of the above.
Have Patriarchal or Athonite teachers ever discouraged isokratema in Church?
D. Koubaroulis: No, as can be heard from their live recordings.
When isokratema is changing, is it subjective as to where exactly it will change (assuming the tetrachord/pentachord rules are respected)?
G. K. Michalakis: What counts most is the text, and not the melody...for a same line with different words, the ison change will change according to the words and its accents..Occidentals don't understand this but that is what Xerodimas taught me.

D. Koubaroulis: In practice yes, it is subjective depending on the isokratis, but there are limits and traditional isokratema knowledge is a prerequisite. Others put more emphasis on the change of text (as mentioned above). Others on the melodic phrases and use those to change the ison. Others (including myself) try to do both, when possible and prefer that there is a master isokratis (or psaltis) who guides the rest of the isokratai as to when they should change.
How did Karas arrive at his theory on ison (tetrachordal usually, double ison, very precise and mechanical, in EBX they have about 6 or more members assigned to just that) and what were his sources?
D. Koubaroulis: That is explained in Angelopoulos' article about isokratema (see above). Karas did not invent the double ison theory but he was the one who made it popular. And Angelopoulos even more.
What makes the difference between a solid Ke and a Pa-Ke (double ison)? Such as in say the Christmas Koinonikon sometimes the EBX move the whole isokratima and other times it is double. What is the basis for when it is and isn't double?
D. Koubaroulis: When the basis of the current tetrachord/pentachord and the basis of the mode are a tetra/penta/octachord away from each other then one can theoretically apply double ison. The second ison is always meant to be softer than the main one. When two isons are applied, the lower pitch one is always the main one. I just made up this rule from experience. I don't know if anyone (Karas?) has written something about it.

An exception to the rule is the example of First Mode doing temporary endings in low ZW. Or Second mode doing endings in BOY. I haven't heard EBX doing double ison in those or similar cases.

Some observations from reading the notes on the page plus prior discussion and knowledge shared: 1) Isokratima seems to have never really been scientifically used or practiced to anywhere near the level of Karas and his students before him. This does not make me say Karas is better, in fact I think how they came up with that style of isokratima shows a lot of what can be good and bad with his method. He apparently looked at all the different practices, read as much theory on it as was available, and decided this was good and that was bad and then streamlined it. The good thing is that he then had a scientific, applicable systematized theory on how to use isokratima and how to apply it to a choir. The bad of it is 1) was it meant to be systematized?
D. Koubaroulis: Is Byzantine Chant at all meant to be systematised? I think yes to some extent but there is no absolute answer (to me at least). My personal belief is that systematising doesn't mean steamrolling all variations into one and only acceptable prototype. Systematising is good in the form of presenting traditional alternatives (something I have tried to do with analogion.com) and pointing out the limits to what is non-traditional.
So the approach Karas and his followers theoretically try to take is "This is one of many ways to chant traditionally" and that their approach to isokratima is the same. Correct?
D. Koubaroulis: Yes.But the philosophy is that from the many traditional ways, Karas' proposal was and is the "state of the art". :-)
In Karas' systematic approach, while based on what he viewed as traditional sources , things are edited through his and only his thoughts and decisions and end up not sounding like anything else that was out there, which begs the question, how can it be traditional if it sounds like nothing else being done at the time or before that time (as best one can tell)?
D. Koubaroulis: I don't think Karas' isokratema sounds that much different from anything else out there. The systematic application of certain "rules" (and of double ison) and "concert" quality of the isokratema distinguishes it from other recordings perhaps.
What qualified, in Karas' eyes, as a traditional source for isokratima and a non-traditional source? I may be worng, but I dont think he lays that out.
D. Koubaroulis: His main concern was to fight against the introduction of vertically-harmonised isokratema which started to become very popular in the 20th century. He clearly identifies that as non-traditional and proposes his method. But it is true, he doesn't say enough about the subject.
It seems that some chanters whose interpretations on pieces are viewed as credible by Karas are completely rejected by some other psaltai as untraditional and wrong. How can a psaltis who has apparently been taught enough to give a traditional interpretation of a piece be so wrong in their isokratima usage when the theory of isokratima was so unsystematized before Karas? Here I am referring to people like Stanitsas, Karamanis and such. I believe (I could be way off on this) Karas said, and I believe I got this from an email posted by Ioannis Arvanitis on the byzantinechant list but maybe he was just saying his own thoughts, that the books of Karamanis were good to learn interpretation, but not good because they weren't as formulaic, but Karamanis writes what he chants so if he does that and his books are good to learn interpretation, then he respected his interpretation, and yet his isokratima is regarded as untraditional.
D. Koubaroulis: Unsystematised doesn't mean each psaltis did as they wish (talking about the trained ones). There were unwritten rules (as with many other things in Psaltiki). For instance quick changes of isokratema inside a melodic phrase were not traditional in the older days (listen to older Patriarchal recordings). Nowadays we hear them all the time from modern protopsaltai and choirs.
At least with interpretation and such there has been a lot written and said on what is and what isn't before that time. How this relates to his whole method and the questions that arise are these for me: If he studied the isokratima so in depth (which he obviously did) and then scientifically developed the "proper" way to perform isokratima, why then does it sound so much different from anything else out there at the time? And here is what I mean by "so different". Despite what GKM wrote, which I believe is true and such, I do not think double ison was very common and I think it was probably a very rare occurrence and never planned, so most of the time it would have been just a solid note. None of the Patriarchal recordings have that. Fr. Dositheos doesn't do it. The tetra/pentachordal style system, while some perform it, a lot of traditional recordings don't. In a recording of the Kekragaria Argai in Tritos chanted by Bamboudakis it rarely moves. Fr. Dositheos recordings rarely have movement like that.
D. Koubaroulis: Exactly. Karas tried to describe this practice of double ison that he experienced and thought that it could be presented formally. There is nothing wrong with that. On the contrary, it gives us a new understanding of Psaltic reality and a reference point to compare approaches and talk about things. And from what I remember, Karas only said that one "may" do double ison temporarily if they want so. He didn't say that it is how things should be done. Trying to systematically apply this formal proposal to each and every possibility of a double ison occuring, changing the music texts to notate it, having special people in the church choir to do the double ison... then it becomes a different story and I agree with you. It loses its spontaneous and organic character and becomes a technical exercise that results in concert-like chanting inside the church which is a debatable goal. That's my personal opinion. Others may find it a step forward in the Psaltic Art.
If this is true for isokratima, which while not easy is definitely basic in comparison with the melos itself, then how can this not have happened within his [Karas'] whole method? Of over-systematically analyzing the traditions and in many ways destroying the organic ways of the tradition itself.
S. Herron: The descriptions GKM gave of what Tsolakidis said of isokratima makes double ison and such very "organic" so to speak in nature. It happened not because the sign said "Pa-Ke_ but because some students knew when to move it and others didn't so they had the ones who didnt keep holding the basis, and thats what formed. There is a certain beauty in that way of double ison developing I find that is taken out of it when laid out in the way Karas has. It takes out the organic nature of how these things developed and how traditions developed. The good though, with isokratima, is that now it gives one something that somebody can teach and that a student can read and quickly get someone up to speed on how the isokratima should be done. It eliminates the initial guesswork, which is how I believe many of the different variations of style began and lead to the near polyphonic nature of some isokratis (Bassilikos comes to my mind). I think this is a good thing, because I would much prefer the isokratima of EBX, Ioannis Arvanitis, the Bilalis brothers, etc., etc. than the isokratima of Bassilikos, Taliadoros, Simonopetra and such.
In the Kekragarion of the First Mode cadences on Zo (so we can say the melody did cadence on Barys and can justify the change of ison). Can we still keep Pa ison throughout the piece?
D. Koubaroulis: Different schools of thought apply here and I don't think there is right or wrong. You can traditionally do three things:

a) co-chant the cadence. This is my preferred approach and it seems what is fairly common Patriarchal and Athonite practice.
b) change ison to ZW for the duration of the cadence to indicate the implied change of mode (from First Mode to Barys). This is what most trained choirs do.
c) keep ison on PA (but at low volume so that it doesn't intervene with the melody which technically is in another mode). When I say this is traditional it means I have heard it many times when isokrates are being very conservative in their changes (see schools of isokratema thought above) or they simply do not know much about changing modes and the only thing they know is keep the basis. It doesn't sound that bad at all when ison is discreet.