In ancient times in the Mediterranean world, it was common to organize sung or chanted music into groups of melodies called "modes" or "tones", each with its own distinctive flavor or characteristics. These tones (often eight in number) sometimes influenced the chant used in each part of the early Christian Church.

In the Byzantine Rite, a complete set of hymns in eight tones was composed to add variety to the liturgy, and give hymnographers (hymn-writers) ample opportunity to praise God and the saints, to teach, and to encourage the faithful. These hymns are largely the work of Saint John Damascene (c. 676-749) and other hymnographers of the eighth and ninth centuries, and are collected in the liturgical book called the Octoechos.

The cycle of eight tones

In the Byzantine liturgical system, each week is assigned to one of the eight tones. The week begins with Sunday - and more particularly, with the service of Vespers on Saturday evening. So each Saturday, we begin singing the hymns in a new tone, in order: tone 1 for a whole week, followed by tone 2 for the next week, and so on. Within each tone, there are hymns for each day of the week, corresponding to the traditional liturgical theme for the day in the weekly cycle. In the course of the year, this 8-week cycle is repeated four or five times.

The assignment of tones to specific weeks begins on Pascha, the greatest feast of the liturgical year. At Vespers on Great and Holy Saturday, at the Lamp-lighting Psalms, we sing the Sunday hymns of Vespers in Tone 1, before continuing with the hymns proper to Great Saturday itself. Then at Matins for Pascha, we sing the Sunday Matins hymns in Tone 1.

Bright Week, the week following Pascha, is the most joyous of the year, and to emphasize the universal nature of the Resurrection, we sing through the Sunday (Resurrection) hymns in all eight tones, one tone per day. Thus, for Bright Monday, we sing the Sunday hymns in Tone 2; on Bright Tuesday, the Sunday hymns in Tone 3; and so on, ending with Tone 8 on Saturday. (Tone 7, traditionally considered the most somber of the tones, is omitted in order to fit the eight tones into seven days.)

On the Sunday after Pascha (Thomas Sunday), we come back to Tone 1, beginning with Vespers on Saturday evening. For the rest of the liturgical year, the tones follow one another in regular procession, one tone per week.

During the Paschal season

Each week in the Paschal season is assigned to one of the eight tones: Thomas Sunday and the following week, Tone 1; The Sunday of the Myrrh-bearers and the following week, Tone 2, and so on. Pentecost Sunday, and the week that follows, would be assigned to Tone 7, but in fact all the hymns for this week are proper to the feast, and the Sunday of All Saints is assigned to Tone 8.

From Pascha until the Sunday of All Saints, we do not actually use the liturgical book called the Octoechos; instead, the appropriate hymns for each Tone are copied into the liturgical book for the Paschal season, the Pentecostarion. We return to using the Octoechos (in Tone 8) after the Sunday of All Saints, and the the week that follows it.

The Sundays after Pentecost

With the second Sunday after Pentecost, we come back to Tone 1, and continue in an uninterrupted cycle of Tones until the next Great and Holy Week:

• Second Sunday after Pentecost - Tone 1

• Third Sunday after Pentecost - Tone 2

• Fourth Sunday after Pentecost - Tone 3

• Fifth Sunday after Pentecost - Tone 4

...and so on. To find the tone corresponding to a particular week, SUBTRACT one from the number of the Sunday that begins the week, DIVIDE BY EIGHT, and keep the remainder. For example, the tone for the 19th Sunday after Pentecost, and the days of the following week, would calculated as follows:

19 - 1 = 18

18 divided by 8 is 2, with a remainder of 2

... so the tone of the week is Tone 2

Each new tone begins at Vespers on Saturday night, and continues through the next Saturday afternoon. On each day we sing hymns from the Octoechos, or Book of Eight Tones, in the tone of the week. EXCEPTION: on feasts of the Lord, and on any major feast which falls on a weekday, we set aside the Octoechos and sing only the feast-day hymns.

The Eight Tones during the Great Fast

Around the 32nd week after Pentecost, we begin preparing for the coming celebration of Pascha. For the preliminary Sundays of the Triodion, and the Sundays and weekdays of the Great Fast, we combine the hymns of the Triodion with those of the eight tones. Each week keeps the tone it would have based on the number of weeks since the previous Pentecost. For this reason, the hymns actually sung during the Great Fast are arranged slightly differently from year to year.

The cycle of the eight tones comes to an end with the conclusion of the Great Fast. For the Great and Holy Week of the Lord's suffering and Resurrection, from Lazarus Saturday to Great and Holy Saturday, the hymns of the Octoechos are completely replaced with those of Great Week. Only on Pascha do we begin again - with the Sunday hymns in Tone 1.

The hymns of the Octoechos

The Octoechos (book of the eight tones) contains the following hymns for each tone (1-8):

For Sunday:

the Lamp-lighting stichera and aposticha (dismissal) stichera at Vespers for Saturday evening

the Sunday troparion and theotokion

the Canons at Compline, Midnight Office and Matins

the sessional hymns, gradual hymns, and prokeimenon at Matins

the Sunday kontakion

the stichera "at the praises" (sung with Psalms 148-150) and the aposticha stichera at Matins

the prokeimenon and Alleluia verses at the Divine Liturgy

For each weekday:

the Lamp-lighting stichera and aposticha (dismissal) stichera at Vespers

the Canons at Compline and Matins

the sessional hymns at Matins

the stichera "at the praises" (sung with Psalms 148-150) and the aposticha stichera at Matins

The hymns of the Octoechos are combined with hymns from the Menaion, Triodion, and Pentecostarion, according to the rules given in the Typikon. In general, the greater the feast, the more material is taken from the other liturgical books, and the less of the Octoechos is used. For great feasts, the hymns of the eight tones are entirely supplanted by hymns for the feast.

The hymns for the Divine Liturgy are often collected also in the reader's book, the Apostol, while anthologies may include just the Sunday hymns in each tone, omitting the weekday hymns.

Hymns from other liturgical books

Hymns in the other liturgical books (such as the Triodion, Pentecostarion, and Menaion) are assigned to particular tones for purposes of singing, but do not follow the orderly cycle of tones described above. This means that at any given service, we may sing hymns from the eight-week cycle (in the tone of the week) combined with hymns for the saint of commemoration of the day (using the specific tones marked for them in the other books).

As a result, the musical "pattern" of the Byzantine rite hardly ever repeats itself, except on major feasts, when the Octoechos is set aside and only the feast-day hymns are sung.

The melodies for the eight tones

Each Church which uses the Byzantine Rite has developed its own system of liturgical chant, much of which is involved with singing the hymns in the eight tones. But while the tone assigned to a given hymn is usually the same in different churches, the actual melody used may be quite different.

*Source: Metropolitan Cantor Institute