A '''canon''' is a structured [[hymn]] used in a number of [[Eastern Orthodoxy|Eastern Orthodox]] services. It consists of nine ''odes'', sometimes called ''canticles'' or ''songs'' depending on the translation, based on compositions (also called odes) found in the [[Bible]] and with one exception, the [[Old Testament]].
The canon dates from the 7th century and was either devised or introduced into the Greek language by [[Andrew of Crete|St. Andrew of Crete]], whose penitential Great Canon is still used on certain occasions during [[Great Lent]]. It was further developed in the 8th century by Sts. [[John of Damascus]] and [[Cosmas the Hymnographer]], and in the 9th century by Sts. [[Joseph the Hymnographer]] and [[Theophanes the Confessor|Theophanes the Branded]].