Basil was born to peasant parents in the 830s at Charioupolis in the Byzantine theme of Macedonia (an administrative division corresponding to the area of Adrianople in Thrace). Contemporary Byzantine Thrace was inhabited by people of Slavic, Greek and Armenian origins. Claims have been made for an Armenian, Slavic, or indeed “Armeno-Slavonic” origin for Basil I. The English Byzantinist John Bagnell Bury dismissed claims of him being of Slavic origin on the basis that the Arabs viewed all Macedonians as Slavs, a view supported by Peter Charanis, a prominent historian who specialized in ethnic studies of the Byzantine Empire. The author of the only dedicated biography of Basil I in English has concluded that it is impossible to be certain what the ethnic origins of the emperor were, though Basil was definitely reliant on the support of Armenians in prominent positions within the Byzantine Empire. During his reign, an elaborate genealogy tree was produced that purported that his ancestors were not mere peasants, as everyone believed, but descendants of the Arsacid (Arshakuni) kings of Armenia and also of Constantine the Great. Members of the Macedonian dynasty would come to use this tree to claim their descent from King Tiridates III of Armenia.