Pope Leo I also has the rare distinction of being named a Doctor of the Church after his death in A.D. 461. This designation is reserved for saints whose writings hold special authority within the Church. As recently as 2008, Pope Benedict XVI discussed Leo the Great, explaining “As the nickname soon attributed to him by tradition suggests, he was truly one of the greatest Pontiffs to have honoured the Roman See and made a very important contribution to strengthening its authority and prestige.”

A n alter piece made of marble.
Medieval texts claim that Pope Leo I went to meet with Attila the Hun after the conqueror’s forces crossed into Italy to plead for mercy on behalf of Rome—a scene depicted here on this marble relief. One text recounts that Attila “straightway promised a lasting peace and withdrew beyond the Danube.”

Photograph By NPL – DeA Picture Library / G. Cigolini / Bridgeman Images

Leo III and the first Holy Roman Emperor

Pope Leo III was another pontiff who led during a formative time in Roman Catholicism. Elected in A.D. 795, Pope Leo III was the pope who crowned Charlemagne as the first Holy Roman emperor. 

“Many historians credit Charlemagne with spreading Christianity across these formerly pagan regions, bringing a common culture and homogeneity to disparate tribes,” according to National Geographic’s Inside the Medieval World. The ruler became defender of the Christian faith and, under him, the continent flourished.

Pope Leo III’s decision to name the emperor as leader of the Church  reaffirmed the relationship between the papacy and the Frankish rulers who would protect the Catholic Church against threats to its land and rights. It also set the stage for actions taken by Pope Leo IX centuries later—when issues of authority and doctrine split Christendom in two.

An illustration of a man with robes and a large hat.
Elected in A.D. 795, Pope Leo III was the pope who crowned Charlemagne as the first Holy Roman emperor—setting the stage for a Great Schism that would come under one of his namesake successors.

Photograph By Tarker / Bridgeman Images

Pope Leo IX and the Great Schism

Born Bruno of Egisheim, Pope Leo IX became the leader of the Catholic Church and ruler of the Papal States, the territory in and around Rome, in A.D. 1049.