When Osman Bey came to power in the Kayi Tribe following the death of his father Ertuğrul Gazi, he established friendly relations with the Tekfurs of Yenisehir and Lefke.

The landlord of Inegol, Aya Nikola was determined to reverse the enroachment of the Turks upon Bithynia and started plundering Kayi markets.

When Osman Bey moved towards Inegol seeking retribution, he was ambushed at the Battle of Mount Armenia [tr] by Nikola and his retinue.

As revenge for all those slain on the mountain, Osman attacked the Byzantine-held Kulacahisar Castle, which is 5 kilometers away from Inegöl and located on the outskirts of Emirdağ to protect the city.

[5] Since the captured Christian people of Kulaca Hisar accepted the rule of Osman Bey, they were not harmed.