The Office of Canonarch
A canonarch was the lead cantor or reader in churches of the Byzantine tradition. The canonarch ensured that the other readers chanted from the correct texts and in the proper tones, and preserved the canonical order of the services through the correct use of the Typicon, reading appointed liturgical texts such as the verses of the prokeimenon.
In a monastery this was a formal obedience, an assigned duty entrusted to a monk. For Gerontius this service of leading the chant was the central labor of his monastic life.