Pertempuran Bapheus

At the plain of Bapheus (; an unidentified site, perhaps to the east of Nicomedia but within sight of the city) on 27 July 1302, the Byzantines met a Turkish army of some 5,000 light cavalry under Osman himself, composed of his own troops as well as allies from the Turkish tribes of Paphlagonia and the Maeander River area. The Turkish cavalry charged the Byzantines, whose Alan contingent notably did not participate in the battle. The Turks broke the Byzantine line, forcing Mouzalon to withdraw into Nicomedia under the cover of the Alan force.