The military campaign of July 17, 1279 becomes a turning point for Bulgarian statehood, when the national leader Ivaylo demonstrates exceptional military skills in the mountainous area around today's town of Kotel. Despite the significant numerical superiority of the enemy, the Bulgarian insurgent manages to defeat the Byzantine army, led by General Murin.
The strategic battle at Devina develops dramatically – Ivaylo skillfully uses the terrain features of the mountain pass, which allows him to neutralize the superiority of the enemy forces. The result is a complete defeat of the Byzantine army, with many enemy soldiers captured and subsequently executed by order of the Bulgarian leader.
The consequences of this victory are extremely significant for the political situation. The second Byzantine army, sent under the command of April, also suffers defeat. Ivaylo's rival – Ivan Asen III, is forced to leave the borders of Bulgaria and seek refuge in Constantinople.
This military success consolidates Ivaylo's position as a charismatic national leader and commander, who not only defends Bulgarian lands but also challenges the mighty Byzantine Empire. The Battle of Devina becomes a key episode of his short but remarkable reign.