Pope from 649. He was a vigorous opponent of the Monothelites. He refused to sign the Typos of the Emp. Constans II and was eventually arrested, taken to Constantinople, and banished to the Crimea; he died soon afterwards. He is the last Pope who is venerated as a martyr. Feast day, 13 Apr.; in the E. also 20 Sept.; in the W. formerly 12 Nov.