Battle of Bapheus: Decisive Ottoman victory over the Byzantines opening up Bithynia for Turkish conquest.
The Battle of Bapheus occurred on 27 July 1302, between an Ottoman army under Osman I and a Byzantine army under George Mouzalon. The battle ended in a crucial Ottoman victory, cementing the Ottoman state and heralding the final capture of Byzantine Bithynia by the Turks.