Mezamir (Greek: Μεζαμηρος, Cyrillic: Мезамир; c. 560) was the chieftain of the Antes, an early Slavic tribal confederation in Eastern Europe, believed to have been active around the year 560, at which time the Avar expanded further into Europe. He was the son of Idariz, and had a brother, Kelagast. Mezamir was recorded by Menander Protector (fl. 558–582). Mezamir was described as "powerful", and had most likely established a Slavic confederation sometime before the 560s, which initially thwarted the Avar khaganate. At this time, the Antes were subject to the Byzantine Empire, ruled by Justinian I (r. 527–565), with the supreme chieftain holding the Byzantine title of archon. The Antes were given old Roman towns and stipends, in exchange for securing the Danube from the Huns, and other Barb