Theodosius the Great (emperor)

Commemorated January 17

For another saint called Theodosius the Great living in the fifth-sixth centuries, see Theodosius the Great (Cenobiarch) .
The holy and right-believing Emperor Theodosius I , also called Theodosius the Great , was the last emperor who ruled over both the eastern and western portions of the Roman Empire. He ruled from 379 to 395. Theodosius I is also known for making Christianity the official state religion of the Roman Empire. He was a strong defender of the Orthodox Christian faith and is a saint . His feast day is celebrated on January 17 .

Source: OrthodoxWiki