Mamia was the son of Vameq I Dadiani, "eristavi" of Odishi, on whose death he succeeded in 1396. During his tenure, the Kingdom of Georgia was subjected to repeated attacks by the Turco-Mongol emir Timur, which devastated the country and shattered its unity. The western Georgian provinces were claimed by scions of the former kings of Imereti, but their attempts to bend the Dadiani into submission went in vain. Mamia continued his predecessors' efforts to aggrandize the duchy of Odishi. In 1414, he went to war against the Abkhazians, but was killed in battle.