Leo I

American

[lee-oh, le-aw] / ˈli oʊ, ˈlɛ ɔ /

noun

Saint, Leo the Great, a.d. c390–461, Italian ecclesiastic: pope 440–461.

Leo I British

/ ˈliːəʊ /

noun

Saint, known as Leo the Great. ?390–461 _ad , pope (440–461). He extended the authority of the papacy in the West and persuaded Attila not to attack Rome (452). Feast day: Nov 10 or Feb 18

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The pontiff of the time, who persuaded Attila to turn his army back and spare Rome, was called Pope Leo I.

From Los Angeles Times • Apr. 13, 2026

Pope Leo I, also known as St Leo the Great, was pontiff between 440 and 461 AD.

From BBC • May 9, 2025

Early medieval popes like Leo I laid the groundwork for the power of the Bishops of Rome, a power the eastern churches largely rejected or ignored.

From Textbooks • Apr. 19, 2023

“It’s an enormous accomplishment for Leo, I have to acknowledge that.”

From Washington Times • Oct. 23, 2022

And even though I suspected Zara just didn’t want me to report Leo, I couldn’t imagine telling all this to Mr. McCabe, anyway.

From "Maybe He Just Likes You" by Barbara Dee

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023