Pope Leo IV

Leo IV was a Roman by birth, the son of a man named Radoald, and a member of the city’s clergy rather than of a documented religious order. The Liber Pontificalis identifies him as natione Romanus. Before his election he was cardinal-priest of the basilica of Santi Quattro Coronati. His year of birth is not recorded in contemporary sources. In April 847, after the death of Pope Sergius II, he was chosen bishop of Rome. The previous year Muslim raiders from Sicily and North Africa had sacked the extra-mural basilicas of Saint Peter and Saint Paul, an event that left Rome exposed and its greatest shrines despoiled. Because of that danger the Roman clergy and people consecrated Leo without waiting for the customary confirmation from the Carolingian emperor Lothair I.

The central achievement of his pontificate was the repair and fortification of Rome. He restored churches damaged in the raid of 846 and undertook a new defensive wall around Vatican Hill and the Borgo, enclosing Saint Peter’s and the adjacent quarter. That circuit, later called the Leonine Wall, and the enclosed district, the Civitas Leonina, were completed and dedicated in 852. He embellished Saint Peter’s with gifts of gold and silver and reorganized the defence of the Tiber mouth. In 849 he blessed a coalition fleet from the maritime cities of Naples, Amalfi, and Gaeta, which defeated a Saracen force off Ostia, an engagement remembered in later tradition as a deliverance of the Roman coast.

In his dealings with the Carolingians he crowned Louis II as emperor in 850. He held Roman synods in 850 and 853 to address ecclesiastical discipline and the case of the ambitious priest Anastasius, later known as Anastasius Bibliothecarius, who was degraded and excommunicated. A later medieval legend, given famous visual form in the Vatican Stanze, attributed to Leo the miraculous quenching of a fire in the Borgo. English sources of a subsequent date state that the young Alfred of Wessex was sent to Rome in the early 850s and received a papal blessing or investiture from Leo; the precise character of that ceremony is not independently confirmed in contemporary Frankish or Roman records, and historians treat a full royal anointing with caution.

Leo IV died in Rome on 17 July 855 and was buried in Saint Peter’s Basilica. After a brief contested episode involving Anastasius, he was succeeded by Benedict III. He has been venerated as a saint in the Catholic Church, with his feast kept on 17 July; the cult belongs to the era before the later formal processes of beatification and canonization, and no individual pope is recorded as having canonized him. His pontificate is remembered above all for the Leonine fortifications and for the restoration of Rome after the shock of the 846 raid.