The Struggle Between Osman Gazi and The Byzantines For Nicaea
By Halil Inalcik
Iznik Throughout History, ed. H. Inalcik (Istanbul, 2003)
Introduction: The Byzantine Empire was forced to turn over all of Anatolia to the Turkish invaders within the twenty-five years following 1071. Suleymansah established the Anatolian Seljukid Sultanate in Nicaea (Iznik) in 1087. Following the Crusader campaign in 1097, which gave back Nicaea to the Byzantines, the emperors from the Comnenus dynasty started a counter attack to recapture Anatolia and reestablished Byzantine sovereignty in the coastal regions of the Aegean, Black Sea and Mediterranean, The emperors did not stop there, but tried to capture Central Anatolia. They built or repaired a number of fortresses and forts to repel and stop the raids of the Turkmen (Turcoman) nomads, who were concentrated at the Western Anatolian borders (especially during tbe reign of Manuel I Comnenus between 1143-1180). Thus, the Byzantines created a strong defense line from Denizli to the lower Sakarya via Uluborlu, Seyitgazi and Eskigehir. In the Sakarya- Sinop region they recaptured Sinop from Emir Kara-Tigin. The junction of the roads coming from the Central Anatolian plateau to Nicaea and Istanbul was Sultan-Oyuku. The Dorylaion (Sar-Oyuk, Sultan-Oyuku fortress, which was rebuilt by Manuel I at a distance of 3 km from Eskigehir, constituted an obstacle preventing the Turkmens from going beyond that point. However, after the Byzantine defeat of 1176 the walls of Dorylaion, were pulled down. Dorylaion was obviously in the hands of the Seljukids before the death of Manuel I (1180). Al-Haravi visited “Sultanyuki” in 1170’s. When the Lascarids (1205-1261) settled in Nicaea, especially during the reign of John III Yatatzes (1222-1254), they confronted the Seljukids in the Dorylaion front and started to attack against the Seljukid expansion initiatives in the Black Sea-Sakarya region (1225-1231). Alaeddin Keykubadl (1220-1232) fought against this move by coming to Ankara during the first years of his sultanate.