On April 10, 847, Pope St Leo IV was unanimously elected and installed as Pontifex Maximus of the Catholic Church. This hasty election deviated from the established tradition at that time, as it proceeded without the consent of the emperor. Recent Saracen invasions during the reign of Leo’s predecessor, Sergius II, had weakened Roman defenses and incited fear among the citizens, thus encouraging a hasty election. Pope Leo IV quickly set to work repairing the damages that the Saracens had inflicted on major basilicas, most notably at St. Peter’s Basilica and St. Paul Outside the Walls. Aware of the external threats the Saracens still posed to the city, Leo also ordered that defensive walls be built around the Vatican. Remains of the walls, known as the Leonine Walls, can still be seen today. Pope Leo also went on the offensive, and in 849, he summoned a fleet, composed of mariner warriors from Naples, Amalfi, and Gaeta, who thwarted an approaching Saracen fleet at The Battle of Ostia, a significant militaristic victory for the papacy. The battle is memorialized in a fresco by Raphael in the Vatican Palace. Pope St. Leo IV died on July 17, 855.
Pope St. Leo IV, San Clemente, Rome, Fresco, 9th century.
Leonine Walls, Rome, 9th century.
The Ascension, San Clemente, Rome, Fresco, 9th century.
The Battle of Ostia, Raphael and students, Vatican Palace, Rome, Fresco, 1514-1515.