The most important prince in the Morea was Guillaume II de Villehardouin (1246–1278), who fortified Mistra (Mystras) near the site of Sparta in 1249. After losing the Battle of Pelagonia (1259) against the Byzantine Emperor Michael VIII Palaeologus, Guillaume was forced to ransom himself by giving up most of the eastern part of Morea and his newly built strongholds. An initial Byzantine drive to reconquer the entire peninsula failed in the battles of Prinitza and Makryplagi, and the Byzantines and Franks settled to an uneasy coexistence.