Definition of Leo I in US English:

Leo I

proper noun

  • (died 461), pope from 440 and doctor of the Church; known as Leo the Great ; canonized as St. Leo I. He defined the doctrine of the Incarnation at the Council of Chalcedon (451) and extended the power of the Roman see to Africa, Spain, and Gaul. Feast day (Eastern Church) February 18; (Western Church) April 11.


Leo I