After its foundation by Osman I in about 1299, the Ottoman Empire expanded across Bithynia in north-west Anatolia by capturing territory from the Byzantine Empire. Osman was succeeded by his son Orhan in about 1324 and, following long sieges, he took the important cities of Bursa (1326) and Nicaea (1331). Next, Orhan besieged Nicomedia from 1333 to 1337. The Byzantine garrison surrendered due to lack of food and resources. Orhan's victory sealed Ottoman control of Bithynia.

Siege of Nicomedia
Part of the Byzantine-Ottoman wars
Result Ottoman victory
Byzantine Empire Byzantine Empire Ottoman Sultanate
Commanders and leaders
Unknown Orhan
Unknown Unknown
Casualties and losses
Unknown Unknown



Following the loss of Nicaea in 1331, Byzantine emperor Andronikos III Palaiologos proposed the payment of tribute to Orhan. Andronikos needed a free hand in the Balkans where Albania, Serbia and Bulgaria were in revolt against Byzantine rule. Orhan rejected his overtures and laid siege to Nicomedia (modern İzmit). In 1337, Andronikos effectively abandoned Nicomedia as he led his army to Albania. The besieged garrison was desperately short of food and supplies by then and so Nicomedia surrendered to Orhan.[1] The inhabitants were allowed to leave the city for Constantinople.[2]



The fall of Nicomedia enabled Orkhan to overrun Bithynia and extend Ottoman rule to the eastern shore of the Bosporus. Apart from Constantinople and some territory in Greece, mainly the Peloponnese, the Byzantines were left with an empire in name only.


  1. ^ İnalcık, Halil (2010). Kuruluş Dönemi Osmanlı Sultanları (1302-1481). İstanbul: Türkiye Diyanet Vakfı İslam Araştırmaları Merkezi. p. 50-51.
  2. ^ İnalcık, Halil (2009). Devlet-i ‘Aliyye Osmanlı İmparatorluğu Üzerine Araştırmalar-I. İstanbul: Kültür Yayınları. p. 41.

Additional source

  • R.G. Grant, Battle: A Visual Journey Through 5,000 Years of Combat, Dorling Kindersley Publishers Ltd, 2005. ISBN 0-7566-1360-4