He participated in many Ottoman campaigns of the second quarter of the 15th century, fighting against the Byzantines as well as against the Crusade of Varna. His repeated raids into the Morea transformed the local Byzantine despotate into an Ottoman dependency and opened the way for its conquest. At the same time, his administration of Thessaly, where he settled new peoples, founded the town of Tyrnavos and revitalized the economy, set the groundwork for Ottoman rule in the area for centuries to come.