Battle of Koyunhisar

Battle of Bapheus

Date	27 July 1302
Location	Between Nicomedia and Nicaea, Bithynia
Result	Ottoman victory

Belligerents

Byzantine Empire

Ottoman Empire

Commanders and leaders

George Mouzalon

Osman I

Strength

~2,000

~5,000

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.

Osman I had succeeded in the leadership of his clan in c. 1282, and over the next two decades launched a series of ever-deeper raids into the Byzantine borderlands of Bithynia. By 1301, the Ottomans were besieging Nicaea, the former imperial capital, and harassing Prussa. The Turkish raids also threatened the port city of Nicomedia with famine, as they roamed the countryside and prohibited the collection of the harvest.

In the spring of 1302, Emperor Michael IX (r. 1294–1320) launched a campaign which reached south to Magnesia. The Turks, awed by his large army, avoided battle. Michael sought to confront them, but was dissuaded by his generals. The Turks, encouraged, resumed their raids, virtually isolating him at Magnesia. His army dissolved without battle, as the local troops left to defend their homes, and the Alans, too, left to rejoin their families in Thrace. Michael was forced to withdraw by the sea, followed by another wave of refugees.

To counter the threat to Nicomedia, Michael's father, Andronikos II Palaiologos (r. 1282–1328), sent a Byzantine force of some 2,000 men (half of whom were recently hired Alan mercenaries), under the megas hetaireiarches, George Mouzalon, to cross over the Bosporus and relieve the city.

At the plain of Bapheus (Greek: Βαφεύς; 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 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.

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