Byzantine Empire under the Leonid dynasty
The Eastern Roman Empire was ruled by the Leonid dynasty from AD 457, the accession of Leo I, to 518, the death of Anastasius I. The rule of the Leonid dynasty coincided with the rapid decline, collapse and eventual fall of the Western Roman Empire. Following the end of the Western Empire, Emperor Zeno abolished the position of Western Roman Emperor and declared himself the sole Roman Emperor.
Source: Wikipedia — Byzantine Empire under the Leonid dynasty (CC BY-SA 4.0)