# Leo the Great becomes pope (440)

URL: https://christianity-history.com/timeline/440-leo-the-great-becomes-pope
Location: Rome
Themes: Papacy

Leo I strengthens papal authority and his Tome defines the two natures of Christ. At this point in the timeline (440), the Bishop of Rome was Pope Sixtus III (31 July 432 – 18 August 440).

## Why it matters
Leo the Great becomes pope mattered because it shaped the authority, policy or public role of the papacy and the Catholic Church.

Pope at the time: [Pope Leo I "the Great"](https://christianity-history.com/popes/pope-leo-i-the-great)

## Sources
- [Wikipedia — Pope Leo I](https://en.wikipedia.org/wiki/Pope_Leo_I)
- [Encyclopaedia Britannica topic lookup — Leo the Great becomes pope](https://www.britannica.com/search?query=Leo+the+Great+becomes+pope)
- [Wikipedia — Age Of Councils (period overview)](https://en.wikipedia.org/wiki/First_seven_ecumenical_councils)