Canon (hymnography)

In Eastern Orthodox and Eastern Catholic liturgical practice, a Canon is a complex and lengthy hymn form, typically sung during Matins (Orthros). It is a structured series of odes, each ode consisting of several troparia (hymns) thematically linked to a biblical canticle.

The structure of a Canon is as follows:

1. Irmos: The opening troparion of each ode, serving as a melodic and thematic model for the subsequent troparia.
2. Troparia: Several troparia following each Irmos, elaborating on the theme introduced by the Irmos and relating it to the feast, saint, or event being commemorated.
3. Katavasia: At certain points during the Canon (often after the 3rd, 6th, 8th/9th odes), the choirs unite and sing the Irmos of the following ode, or a specially designated Katavasia, in a more solemn manner. This practice evolved from singers descending from their respective stalls to sing together.

The usual number of odes in a Canon is nine, modeled after the nine biblical canticles (Old Testament canticles for odes 1-8, and the Magnificat and Benedictus from the New Testament for odes 9 and 7 respectively). However, Canons can sometimes have fewer odes; for example, a "Triodion" has only three. Certain special days, like Holy Saturday, feature a "Great Canon" which includes all nine odes.

The biblical canticles associated with each ode are:

• Ode 1: Song of Moses after crossing the Red Sea (Exodus 15:1-19)
• Ode 2: Song of Moses before his death (Deuteronomy 32:1-43) - Usually omitted in Great Lent due to its penitential nature.
• Ode 3: Prayer of Hannah (1 Samuel 2:1-10)
• Ode 4: Prayer of Habakkuk (Habakkuk 3:2-19)
• Ode 5: Prayer of Isaiah (Isaiah 26:9-20)
• Ode 6: Prayer of Jonah (Jonah 2:3-10)
• Ode 7: Prayer of the Three Holy Children (Song of the Three Holy Children 3-22)
• Ode 8: Song of the Three Holy Children (Song of the Three Holy Children 29-34, 35-68)
• Ode 9: Magnificat (Luke 1:46-55) and Benedictus (Luke 1:68-79)

The Canon is a highly developed form of liturgical poetry, requiring considerable theological and poetic skill in its composition. It is a central and beautiful part of the Orthodox and Eastern Catholic liturgical tradition.