Since the Treaty of Nymphaeum in 1214, the Latin Empire had controlled the northwestern littoral of Asia Minor, from Nicomedia to Adramyttium, as well as the Mysian plain.

In the ensuing battle, Vatatzes achieved a decisive victory; among the captives taken were the two Laskaris brothers, who were blinded.

His narration describes the Nicaean army as being almost defeated, before the Emperor, with a few men, turned the tide, "For he took hold of a spear and struck the enemy".

Threatened both by Nicaea in Asia and Epirus in Europe, the Latin emperor sued for peace, which was concluded in 1225.

According to its terms, the Latins abandoned all their Asian possessions except for the eastern shore of the Bosporus and the city of Nicomedia with the surrounding region.