In the Bulgarian Empire, there were internecine struggles as well but the new Emperor Ivan Alexander knew that the decisive confrontation with Byzantium was yet to come and decided to improve his relations with the Serbs.

In the summer of the same year, the Byzantines gathered an army and without a declaration of war advanced towards Bulgaria, looting and plundering the villages on their way.

The Byzantines seized several castles because Ivan Alexander's attention was focused towards fighting the rebellion of his uncle Belaur in Vidin.

The Emperor decided to act swiftly during the course of five days, when his cavalry covered 230 km to reach Aitos and face the invaders.

The eight-year-old son and successor of the Bulgarian emperor Michael Asen was married to the daughter of Andronikos, Maria, cementing the peace between the two states.