Battle of Pelekanon

Timeline

1. 1328–1329Nicomedia · BithyniaOrhan, based at Bursa, maintained a blockade of Nicomedia and Nicaea, which still owed allegiance to Constantinople. With food running short, Andronikos III decided to campaign in person, hoping to open a route in open battle and reassert deterrence over Bithynia—the emperor's first attempt to face the Ottoman main force head-on.
2. 1329Pelekanon · BithyniaThe Byzantine army advanced along the Marmara coast to near Pelekanon. Ottoman light cavalry harassed them continuously, drawing them into battle on unfavorable ground. Andronikos III was wounded, command broke down, and the Byzantine lines wavered. Generals including John Kantakouzenos organized a retreat, and the field campaign failed.
3. 1329–1331Bithynia · BithyniaAfter the defeat at Pelekanon, Byzantium could no longer send a field army large enough to relieve Nicaea or Nicomedia. Nicaea fell in 1331, and Nicomedia changed hands within a few more years. The battle marked Byzantium's shift in northwestern Anatolia from holding isolated cities to full retreat, while the Ottomans rose from an inland beylik to a maritime power.