Defense against Monothelitism
Sophronius stands among the foremost early opponents of Monoenergism and Monothelitism, the seventh-century teachings that Christ acted by a single divine energy or possessed only a single will. As a monk and later as patriarch he argued that this compromised the full humanity of Christ and amounted to a subtle revival of Monophysitism.
In 633 he traveled to Alexandria and Constantinople seeking to dissuade the patriarchs from the doctrine. Upon his election in 634 he issued a synodical letter, addressed to Pope Honorius I and the Eastern patriarchs, expounding the Orthodox confession of Christ's two natures. He also compiled a large florilegium of patristic texts supporting the doctrine of Christ's two wills. Though much of his polemical writing on the controversy has been lost, his synodical letter survived and was later read at the Third Council of Constantinople, which formally condemned Monothelitism.
The fall of Jerusalem
Sophronius's patriarchate coincided with the Arab conquest of the Holy Land. His Christmas sermon of 634 already lamented that Saracen forces held Bethlehem, blocking the customary procession from Jerusalem. As the city itself came under siege, he led its Christian community through the crisis.
When Jerusalem capitulated to the Caliph Umar around 637, Sophronius negotiated the terms of the surrender, by which the Christians of the city were granted security for their persons, churches, and worship in return for the payment of tribute. He died not long after the city's fall.
Writings
Sophronius was a prolific author. His surviving works include a number of homilies, among them sermons on the feasts of the Church, and a body of twenty-three anacreontic poems treating liturgical themes and contemporary events, including the Muslim siege of Jerusalem. Several of these poems describe the sacred topography of Jerusalem, naming sites such as Calvary, the Constantinian basilica, Mount Sion, and Gethsemane.
Among his hagiographical works, he composed the Life of Mary of Egypt, which came to be read during the services of Great Lent in the Byzantine tradition, and an encomium of the Alexandrian martyrs Cyrus and John, written in gratitude for what tradition holds was a miraculous healing of his eyesight.