Sembrouthes
Sembrouthes was a king of the Aksumite Empire in Africa and reigned probably in the second half of the third century. He is only known by a written in Greek inscription, which was found in Daqqi Mahari, just north of Aksum. The text of the short inscription reads:
King of the kings of Aksum, Sembrouthes came ( and ) has ( this inscription ) consecrated in 24 of Sembrouthes, the Great King.
So Sembrouthes reigned at least 24 years and he is also the first ruler of Aksum with the title King of Kings.