(antipope Jan. 844)
On the death of Gregory IV (25 Jan. 844) the populace of Rome, with violent demonstrations, proclaimed a deacon named John with no known links to the aristocracy as his successor, and seizing the Lateran palace enthroned him there. The lay aristocracy, however, elected the elderly, nobly born archpriest Sergius, ejected John from the Lateran, and swiftly crushed the opposition. Sergius' consecration was rushed through without waiting for imperial ratification. Although some of his supporters wanted John put to death for what they considered his presumption, his life was spared by Sergius and he was confined in a monastery. Nothing further is known about him.
LP ii. 86 f.JW i. 327Levillain ii. 830–31 (F. Marazzi)EC vi. 582 (P. Brezzi)