Ivan Asen I of Bulgaria

Ivan Asen I, along with his brother Peter, led a rebellion of Bulgarians and Vlachs against Byzantine rule. The uprising began after the brothers demanded a pronoia (land grant) from Emperor Isaac II Angelos and were refused. They proclaimed the restoration of the Bulgarian Empire, sparking a war that would eventually liberate much of Bulgaria.

Ivan Asen I and his brother Peter proclaimed the restoration of the Bulgarian Empire in the city of Tarnovo. They declared themselves emperors (tsars), claiming continuity from the First Bulgarian Empire. This act established the Second Bulgarian Empire, with Tarnovo as its capital. The proclamation was accompanied by the consecration of a new patriarch.

Ivan Asen I's forces ambushed and defeated a Byzantine army under Emperor Isaac II Angelos in the Tryavna Pass. The Byzantines were caught in a narrow mountain pass and suffered heavy losses. This victory secured Bulgarian control over the Balkan Mountains and forced the Byzantines to recognize the Second Bulgarian Empire's existence.

Ivan Asen I was assassinated by his cousin Ivanko, who had been accused of plotting against him. The murder occurred during a hunting trip. Ivanko briefly seized power but was soon overthrown by Peter, Ivan's brother. This assassination destabilized the new empire and led to a period of internal conflict among the Asen dynasty.