Definition of Leo I in English:

Leo I

proper noun

  • (d.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 (in the Eastern Church) 18 February; (in the Western Church) 11 April.

Pronunciation

Leo I

/ˈliːəʊ/