Leo III was elected Pope on December the 26th 795, the same day his predecessor Adrian was buried. Before his election he had held the offices of Cardinal-Priest and Vestiarius (chief of the Pontifical treasury and wardrobe).
Some say that the speed of his election was due to the fear of the Cardinals that the Franks might interfere with their freedom of election if they did not come to decision quickly.
Leo sent a letter to the Frankish King Charlemagne he also sent him the keys to the confession of St. Peter and the standard of Rome. He did this to show his respect for the King and in return Charlemagne sent Leo a letter of congratulations and a large part of the treasure the King had captured from the Avars. It was this wealth that enabled Leo to contribute so significantly to many charitable institutions in Rome.
His good relationship with Charlemagne proved to be vital during his Pontificate because he was hated by many of the relatives of his predecessor Adrian. On the 25th of April 799 Leo was attacked in the street by armed who tried to tear out his tongue and gouge out his eyes as this would render him unable to fulfil the office of Pope. Leo was left bleeding in the street but was later taken to the monastery of St. Erasmus where he made a remarkable recovery and he maintained full use of his eyes and tongue.
He escaped from the monastery and went to Charlemagne who received him with great honour even though the Popes enemies had tried to poison the King against him with vicious rumours.
Leo later returned to Rome escorted by some of the Frankish King’s guard. When he arrived at Rome all the people in the city rejoiced. The Pope’s enemies were tried by Charlemagne’s envoys and since they could prove neither Pope Leo’s guilt nor their own innocence they were sent to France as prisoners.
Leo’s enemies had made a number of accusations against the Pope but when Charlemagne came to Rome in 800 none of the Bishops considered themselves fit to judge the Pontiff. Leo did however make a public speech in which he denied all the accusations. He also specifically requested that his accusers’ (and attackers’) sentences be reduced from execution to exile.
Perhaps the most important thing that Pope Leo did during his reign was crown Charlemagne Holy Roman Emperor. The story says that Charlemagne was kneeling before the Confession of St. Peter with his head bowed when the Pope approached him and placed a crown upon his head at which point all the people gathered called out in one voice.
”To Charles the most pious Augustus, crowned by God, to our great and pacific Emperor life and victory!”
This theoretically reunited the Empire of the west but while the Pope appeared to be giving power to a secular figure he also created the idea that the crown was God-given indirectly making the church more powerful.
Leo maintained his friendship with the Emperor, the latter is even said to have consulted Leo about the dividing of the Empire between his sons. One thing Leo tried to do was arrange a marriage between the Emperor and the Empress Irene which would have effectively united all the empire under Charlemagne but unfortunately the Empress’s personality proved a problem and the, politically excellent, plan fell through.
Leo settle a number of religious disputes across the Empire throughout his reign and was particularly influential in England. He also contribute to a large number of charities and founded numerous churches.
Everything went well until the death of the great Emperor. A new conspiracy against the Pope was formed but this time Leo was warned and the conspirators were caught and executed. Soon after a number of nobles from the Campagna took up arms and began plundering the Italian countryside they were about to march on Rome itself when the Duke of Spoleto came to the Pope’s aid (under orders from the Italian King)and the rebels were defeated.
Leo devoted the rest of his life to helping the poor and encouraging art.
Pope Leo III died in 816 and was buried in St. Peter’s on the 12th of June.
He was canonised in 1673.