Emperor Leo I was a Byzantine emperor who ruled from 457 to 474 AD. He is known for his military successes and efforts to strengthen the empire's defenses against invasions, particularly from the Huns and Goths. Leo I was the first Byzantine emperor to be crowned by a patriarch, which helped establish the church's influence in imperial affairs. Leo I also played a significant role in the development of the Council of Chalcedon in 451 AD, which addressed key theological disputes within Christianity. His reign marked a period of relative stability and consolidation for the Byzantine Empire, setting the stage for future emperors.