The retreating imperial army slowly marches southwards,…

The retreating imperial army slowly marches southwards, their troops and baggage train stretching for kilometers.

The Bulgarian monarch having deduced that his opponent will go through the Tryavna Pass, the Bulgarians reach the pass before them and stage an ambush from the heights of a narrow gorge.

The imperial vanguard concentrates their attack on the center, where the Bulgarian leaders are positioned, but once the two main forces meet and hand to hand combat ensues, the Bulgarians stationed on the heights shower the Greek force below with rocks and arrows.

In panic, the imperial army breaks up and begins a disorganized retreat, prompting a Bulgarian charge, who slaughter everyone on their way.

Isaac II barely escapes; his guards have to cut a path through their own soldiers, enabling their commander's flight from the rout.

The Byzantine historian Niketas Choniates writes that only Isaac Angelos escaped and most of the others perished.

The battle is a major catastrophe for Constantinople.

The victorious army captures the imperial treasure including the golden helmet of the East Roman Emperors, the crown, and the Imperial Cross, which is considered the most valuable possession of Constantinople’s rulers—a solid gold reliquary containing a piece of the Holy Cross.

It is thrown in the river by an Orthodox cleric but is recovered by the Bulgarians.

These trophies will later became the pride of the Bulgarian Treasury and will be carried around the capital, Turnovo, during official occasions.