Euphemius was a character in Season 5.
Euphemius was a Byzantine admiral, probably born in Messina. Around 826, the Byzantine Emperor appointed a new governor of Sicily called either Constantine or Photinus, who in turn entrusted a naval command to Euphemius, a landowner with a large following. Accused on a perhaps trumped-up charge of abducting a young nun from a convent, he organized an uprising against the Byzantine Emperor, Michael II, and, after some military successes, proclaimed himself emperor in Syracuse, independent from Constantinople. In practice, he was a charismatic chief, and, respected as a king, the title of emperor meant that he dominated the whole territory of the island. Realising that he would be defeated by Byzantine troops when reinforcements were sent from the East, he appealed to Muslim leaders of Ifriqiya, where he asked the help of Arabs to take Sicily and Malta from the Byzantines. In the high summer of 827 he joined his forces with a large fleet commanded by Asad ibn al-Furat, but died later that year, killed by members of the imperial garrison at Castrogiovanni. He is considered to be the man who initiated the Arab invasion of Sicily and Malta and the beginning of the two-century Islamic domination on the island as the Emirate of Sicily.