Son of Syrian immigrants. Educated at Palermo. Priest in Rome. Canon regular of Saint John Lateran. First named cardinal-priest of Saint Susanna by Pope Leo II. Elected pope on 15 December 687, chosen over the priest Theodore and the archdeacon Paschal who was later found to be dabbling in magic and stripped of his position.
Emperor Justinian II felt that his authority extended to all matters, including the Church. Sergius refused to lend papal approval to edicts issued by Justinian and the Synod of Trullan in 692, which Justinian had convened. The emperor ordered the arrest of the pope, but the citizens of Rome arose to defend him. When additional troops arrived, fighting broke out. Zachary, leader of the Emperor's troops, was forced to seek sanctuary and the protection of Sergius, was eventually reduced to hiding under the Pope's bed. Sergius ordered a complete halt to the violence; many of the troops sent to arrest him sided with the pope, and Zachary and his remaining soldiers were permitted to withdraw.
Islam made large advances in North Africa during Sergius's reign, including capturing Carthage and ending Roman power in the region after 850 years. Sergius reconciled the Church of Aquileia to Rome. Ordered processions in Rome on the days of the Annunciation, Nativity, Assumption of the Blessed Virgin, and Purification. Sent missionaries to Friesland and Germany. Defended Saint Wilfrid. Baptized Caedwalla as king of the West Saxons in 689. Ordained Saint Willibrand as bishop of the Frisans in 695. Introduced the Agnus Dei to the Latin eucharistic rites. Created ninety-six bishops, eighteen priests, and four deacons.
at Palermo, Sicily
15 December 687
7 September 701 of natural causes in Rome; interred at the Vatican.