Battle of Tryavna The Battle of Tryavna ( ) occurred in 1190 , in the mountains around the contemporary town of Tryavna , central Bulgaria . The result was a Bulgarian victory over the Byzantine Empire , which secured the successes achieved since the beginning of the Rebellion of Asen and Peter in 1185 . Origins of the conflict . After his second campaign in Moesia and the fruitless siege of Lovech in 1187 , the Byzantine Emperor , Isaac II Angelos , was forced to conclude a truce , thus " de facto " recognizing the independence of Bulgaria . Until 1189 , both sides observed the truce . The Bulgarians used this time to further organize their administration and military . When the soldiers of the Third Crusade reached the Bulgarian lands at Niš , Asen and Peter offered to help the Emperor of the Holy Roman Empire , Frederick I Barbarosa , with a force of 40 , 000 against the Byzantines . However , the relations between the Crusaders and the Byzantines smoothed , and the Bulgarian proposal was evaded . The battle . The Byzantines prepared a third campaign to revenge for the Bulgarian actions . Like the previous two invasions , they managed to overcome the passes of the Balkan mountains . They made a feint indicating that they would pass near the sea by Pomorie , but instead headed to the west and passed through the Rishki Pass to Preslav . The Byzantine army next marched westwards to besiege the capital at Tarnovo . At the same time , the Byzantine fleet reached the Danube in order to bar the way of Cuman auxiliaries from the northern Bulgarian territories . The siege of Tarnovo was unsuccessful . The defense of the city was led by Asen himself and the morale of his troops was very high . The Byzantine morale , however , was quite low for several reasons : the lack of any military success , heavy casualties and particularly the fact that the soldiers ' pay was in arrears . This was used by Asen , who sent an agent in the guise of a deserter to the Byzantine camp . The man told Isaac II that , despite the efforts of the Byzantine navy , an enormous Cuman army had passed the river Danube and was heading towards Tarnovo to relive the siege . The Byzantine Emperor panicked and immediately called for a retreat through the nearest pass . The Bulgarian Emperor deduced that his opponent would go through the Tryavna Pass . The Byzantine army marched southwards , and their troops and baggage stretched for kilometers . The Bulgarians reached the pass before them and staged an ambush from the heights of a narrow gorge . The Byzantine vanguard concentrated their attack on the centre where the Bulgarian leaders were positioned . Once the two forces met , and hand to hand combat had begun , Bulgarians stationed on the heights showered the Byzantine force below with rocks and Arrows . In panic , the Byzantine force broke up and began a disorganized retreat , prompting a Bulgarian charge . The Bulgarians slaughtered everyone on their way . Isaac II Angelos , the Byzantine Emperor , barely escaped ; his guards had to cut a path through their own soldiers , enabling their commander ' s flight from the rout . The Byzantine historian Nikita Chroniates wrote that only Isaac Angelos escaped and most of the others perished . The battle was a major catastrophe for the Byzantines . The victorious army captured the Imperial treasure of Byzantium including the golden helmet of the Byzantine Emperors , the crown and the Imperial Cross which was considered the most valuable possession of the Byzantine rulers - a solid gold reliquary containing a piece of the Holy Cross . It was thrown in the river by a Byzantine cleric but was recovered by the Bulgarians . These trophies later became the pride of the Bulgarian Treasure and were carried around the capital , Tarnovo , during official occasions . Aftermath . The victory was very important for Bulgaria . Up to that moment , the official Emperor was Peter IV but after the major successes of his brother he gave the power to his smaller brother Asen who was proclaimed Emperor later that year . Officially , Peter preserved his title and ruled from Preslav but the state now governed by Ivan Asen I . In the next two years , he liberated many lands to the west and south - west including Sofia and Niš . His troops looted Thrace and the Byzantines were powerless to resist the Bulgarian attacks .