Changes

As with all other Orthodox [[church]] music, a canon is sung by a [[choir]] or [[cantor]] in ''a cappella'' [[chant]]. An ode of the canon is begun by singing the Biblical ode from its beginning. At some point this is interrupted by an introductory stanza called an ''[[irmos]]'', "link", which poetically connects it to the subject of the canon. Following the irmos and sung alternately with the subsequent verses of the ode are a series hymns comprising a single stanza each, or ''[[troparion|troparia]]'', set in the same melody and meter as the irmos, that expand on its theme. The ode is completed with a final stanza called ''katavasia'', which might or might not be present depending on the service and occasion, and which also varies accordingly. It might be a repetition of the irmos, the irmos of the second canon when more than one canon is being sung together, the irmos of the canon for an upcoming major feast day, or some other verse prescribed by the service books. (Katavasia means "coming down" and the verse is so called because as originally performed the two choirs would descend from their places on the left and right sides of the church to sing it together in the middle.)