The southern portion, which extended north to the southern end of the second cataract of the Nile was known as Upper Nubia; this was called Kush (Cush) under the 18th-dynasty pharaohs of ancient Egypt and was called Ethiopia by the ancient Greeks.
Ezana (active early to middle 4th century) was an Ethiopian king during the Axumite period. His reign marked a turning point in Ethiopian history because Christianity became the state religion when he became the first Christian king.
Procopius, John of Ephesus, and other contemporary historians recount Kaleb's invasion of Yemen around 520, against the Himyarite king, Yusuf Asar Yathar, known as Dhu Nuwas, a Jew who was persecuting the Christian community of Najran.