Among the various psalm-based Byzantine genres of chant the prokeimena are notable for covering virtually the entire Psalter: it is hard to find a psalm missing from the vast prokeimenon repertory. Thus one of the earliest comprehensive liturgical sources – The Typikon of the Great Church in Constantinople (Staurou 40, 10^th cent.) – contains about 190 prokeimena derived from the texts of 141 psalms. Most of these chants are intended for the weekdays of Lent, and are arranged in the numerical order of the psalms from which they are taken. Beginning on the First Monday of Lent with four prokeimena derived from Psalms 1 – 4, and keeping the pattern of four consecutive texts a day (Monday through Friday) for more than six weeks, the sequence finally reaches Ps. 137 on Great and Holy Wednesday. Table 1 shows the series in detail.

The Typikon of the Great Church evenly divides the Lenten prokeimena between two offices: Tritoekte (Terce-Sext) and Vespers. Tritoekte was a special Lenten office centered on the preparation of Catechumens for Baptism. It originated in the early stages of the cathedral worship, fully developed by the eight century, and disappeared with the decline of the Great Church. Traces of Tritoekte, however, are still visible in modern-day Triodion, and the prokeimena are among the few surviving elements of the ancient office.

In both old and modern liturgical sources the Lenten prokeimena are bound to the lectio continua, that is, the reading in their totality of three Old Testament books: Genesis, Proverbs, and Isaiah. The numerically ordered lessons from these books alternate with the numerically ordered psalm texts of the prokeimena, setting a daily pattern for the six weeks of Lent, Monday through Friday, as follows:

Table 2

During the first three days of Holy Week the prokeimena continue their psalm-borrowed sequence, while the readings change respectively to Ezekiel, Exodus, and Job. From Great and Holy Thursday on, special services take place.

The “continuous reading” of the Old Testament is considered an early practice dedicated to the indoctrination of Catechumens at the time when Lent was still the pre-baptismal season of the Church. The “continuous psalmody,” brought out by the prokeimena series, most likely has the same liturgical roots as the readings with which it alternates.

There is little doubt that originally psalms were chanted in whole, and the prokeimenon form (consisting of a few verses) gradually developed through shortening the texts. What did not change in the course of time was perhaps the responsorial rendering of the psalms: the prokeimenon genre still employs a chosen verse as a response to the rest of the verses derived from a given psalm. In this respect, the word “prokeimenon” (“what lies before,” “what precedes”) could indicate the particular structure, in which the response not only follows each verse, but also precedes the psalm itself.

Another widely accepted explanation of the term “prokeimenon” is that this chant usually precedes a reading, as in the case of the observed segments of Tritoekte and Vespers (Table 2). The specific arrangements of prokeimena alternating with readings agree with an old-established custom, which was even decreed by the Council of Laodicea in the second half of the fourth century, namely, the psalms were not to be sung immediately after each other, but lessons were to be read between them.

The latter part of the fourth century is also regarded as the time when Tritoekte presumably occurred; it is quite possible that the continuous chanting-and-reading presentation of the Old Testament became part of the office from the very beginning. The earliest documented Tritoekte, however, dates from the eight century (MS Barberini gr. 336).

The texts of the prokeimena themselves cannot be traced much further back than the tenth century, as they appear in the fully elaborated liturgical system of the Typikon of the Great Church. Evidently, by that time some Lenten prokeimena had spread beyond the initial series serving on different occasions throughout the ecclesiastical year. For instance, the prokeimenon Το στομα μου λαλησει σοφιαν (Ps. 48:4^a.2) intended for Vespers on the Third Tuesday of Lent as a part of the numerical sequence, is simultaneously prescribed for the Liturgy on certain commemorations of the Fathers of the Church; in a similar way the prokeimenon for Tritoekte on the Third Thursday of Lent Ο Θεος, εν τω ονοματι σου (Ps. 53:3^a.4^a) is fixed to the evening office on most Wednesdays of the year.

The latter example, along with other prokeimena to be sung weekly at Vespers, is found in a separate group at the end of the Typikon. There are several such groupings especially arranged for recurrent use in worship; one of them, entitled Προκειμενα αναστασιμα και της λειτουργιας, is gathered entirely from the Lenten series.

Altogether twenty-five prokeimena – the ones marked with asterisks (*) on Table 1 – were borrowed from the Lenten series and placed elsewhere, hence in a new liturgical situation. In order to suit their new function, the selected prokeimena apparently underwent a considerable musical improvement and made their way into the melismatic repertory of the Psaltikon. Would it be feasible, then, to link the melismatic melodic versions back to the psalmody of the Lenten prokeimena? The musical evidence of the Typikon of the Great Church, though limited, reveals features of a very simple chanting practice, which was most likely preserved and transmitted orally.

The modal signatures of the Lenten prokeimena (columns “Mode” on Table 1) show the predominant employment of two modes: Fourth Authentic and Second Plagal. Out of 132 chants in the series, 110, or about 83 percent, are set in one of these modes. As for the 17 percent left for the remaining six modes, they coincide remarkably with the prokeimena used for different occasions outside of the Lenten period (the ones marked with asterisks on Table 1). It appears, therefore, that modal variety was brought by the prokeimena having been adjusted to some new conditions and returned back to the Lenten series; in other words, due to outside borrowings, the primitive modal system was transformed into a system of eight modes. Thus, in addition to the liturgical data, the musical evidence points once again to the ancient origin of the Lenten prokeimena – origin, which precedes the introduction of the eight-mode system, and dates accordingly before the sixth century.

Finally, a word must be said about the distribution of the genre throughout the ecclesiastical calendar. Since the prokeimena take part in virtually every office every day of the year, there are many possible ways to classify them. From our viewpoint, a line can be drawn between the prokeimena derived from the Lenten series, and those not connected to it.

The prokeimena that originated in the Lenten sequence tend to appear on old-established celebrations, such as Easter, Pentecost, and Ascension. With their non-specific devotional texts, however, these chants do not relate immediately to any particular feasts.

On the other hand, most of the prokeimena that came into existence independently of the Lenten sequence are obviously composed for the occasion: the psalm verses chosen for them perfectly fit the celebration. For example, the prokeimena to precede the Gospel on Sunday Matins carry the idea of the Resurrection: Νυν αναστησομαι, λεγει Κυριος (Ps. 11:6^c.7), Εξεγερθητι, Κυριε ο Θεος μου (Ps. 7:7^c.2^ab), Αναστα, Κυριε, βοηθησον ημιν (Ps. 43:27^ab.2^ab), etc. Special prokeimena were composed for numerous fixed feasts: Ευαγγελιζεσθε ημεραν (Ps. 95:2^b.1) for Annunciation, Ο ποιων τους αγγελους (Ps. 103:4^ab.1^a) for the days devoted to the Holy Archangels, and many more.

These “compositions for the occasion” have gradually filled the calendar in a long process of bringing the prokeimenon repertory up to date. An earlier long process of responsorial psalm singing had already brought the prokeimenon genre to life, most probably, through the continuous Lenten psalmody.