Initially appointed as Co-Emperor by Leo II, Zeno was the son in law of Leo I, married to his daughter Ariadne. Leo II was his and Ariadne’s son, only seven years old in February 474, having become emperor in January upon the death of his grandfather. When Leo II unexpectedly sickened and died in November of that year, he left his father, who had never been intended to be Emperor, the sole ruler of the Byzantine Empire.
Zeno was not well-liked – he was seen as a foreigner (his real name was Tarasis – he’d changed it to the Greek Zeno in hopes of being more acceptable to the Byzantines) and an interloper. He was dethroned in a rebellion a year later, only to claw his way back to the top eighteen months after that.