pope (672–676) who was the first pontiff to date events in terms of his reign, which began with his election on April 11, 672.

Adeodatus played no known role in the political events of the day or in the liquidation of monothelitism (Monothelite) (a heresy teaching that Christ had only one will), although he did defend orthodoxy on the issue. He devoted his attention to restoring churches in a state of disrepair. A Benedictine monk, he took the Abbey of St. Peter and St. Paul (St. Augustine's) under his protection; he improved the Monastery of St. Erasmus; and he seems to have recognized the exemption of the Abbey of St. Martin of Tours from episcopal authority. Some hagiographers style him “Saint” and give him June 26 as a feast day, but the Bollandists, who edit and publish the Acta Sanctorum, insist that he had no cult and therefore is not entitled to a feast day.