The man who would become Pope St. Leo IV was born around 790. He was a Roman by birth, although his family roots were in Lombardy in northern Italy. A Benedictine monk at the monastery of St. Martin in Rome, he became a cardinal under the pontificate of Sergius II, pope from 844 to 847.
We are publishing a summer series on the 13 popes who bore the name Leo before the current pontiff. The fourth episode focuses on Pope Leo IV (847-855).
The end of this pontificate was marked by the dramatic events of the Arab invasions. In August 846, the Saracens sacked Rome, leading Sergius II to consider strengthening the Vatican's fortifications. This project would be the great work of his successor.
Restorer of Rome
Elected unanimously by popular acclamation on April 10, 847, Leo IV was immediately enthroned and consecrated—without waiting for the consent of the Frankish emperor, which it was customary to obtain at the time. The urgent and vulnerable situation of the city of Rome led him to build a rampart around the Vatican.
This project was completed in 852, tracing the contours of the “Leonine City,” a name that has remained for more than a millennium. He also had other places in the area of Rome fortified, and led a restoration of St. Peter's Basilica, which had been damaged in the attack of 846.
In addition to an earthquake that was one of the most severe in the history of Rome, the decidedly dramatic start to his pontificate was also marked by a fire in the Borgo, the working-class neighborhood adjacent to the Vatican.
A miracle worker
Leo IV miraculously extinguished the blaze with his blessing alone. According to a tradition reported in the Liber Pontificalis, Leo IV made a solemn sign of the cross from the outer balcony of St. Peter's Basilica, to the left, in the direction of the Borgo, which immediately caused the flames to recede. The population and the basilica were thus saved.
This event, which took place in 847, inspired Raphael to paint a fresco several centuries later entitled The Fire in the Borgo. This fresco, currently on display in the Vatican Museums in the Raphael Rooms, was painted between 1514 and 1517.
Beyond its evocation of this historical episode, this fresco, which combines Christian references and characters from pagan mythology, alludes to the pacifying role of the pope amid the outbreak of wars.
In order to combat the Saracen threat, Leo IV forged alliances with the rulers of various duchies on the coast of present-day Italy, notably those of Amalfi, Gaeta, Naples, and Sorrento. The victory of their coalition against the “Barbary pirates” at the Battle of Ostia in 849 was also depicted in a fresco by Raphael.
Kingmaker
Furthermore, Leo IV had good relations with Emperor Lothair I, Emperor of the West from 840 to 855. This led him to crown the emperor’s son, Louis II the Young, to serve as co-regent. He held this position from 850 to 855, and then was Emperor of the West in his own right after his father's death, until 875.
Many rulers of European Christian kingdoms thus requested to be crowned by the pope in order to obtain recognition of their sovereignty by “divine grace.”
The “Restorer of Rome,” as he was later nicknamed, was also a pope renowned for his integrity and generosity towards the poor. He also worked to strengthen discipline among the clergy and purity of the faith, encouraging the organization of synods throughout Europe, notably in Paris, Lyon, and England.
Earlier in the series:
Leo the Great
Leo II
Leo III
