Cyrus was placed on the patriarchal throne in 705 by Emperor Justinian II, as a replacement for the deposed Patriarch Callinicus I. Soon after Justinian's decline and eventual fall in December 711, Kyros was replaced by the new Emperor Philippicus with Patriarch John VI, who shared Philippicus' Monothelite sympathies.
Cyrus became patriarch in 705 after Emperor Justinian II removed the previous leader Callinicus I. Following Justinian's decline and eventual overthrow in December 711, Cyrus was succeeded by a new emperor Philippicus with Patriarch John VI, who shared Philippicus' views on Monothelitism.