Byzantine domination continued until 1185 when revolt, organized and led by two brothers of noble birth - Asen and Petar took place. The revolt was successful and cleared the way for the establishment of Second Bulgarian Empire with Tarnovo becoming capital, and enthronement of a new royal dynasty - the Asenovtsi dynasty. But Bulgarian Empire reaches his previous might no sooner than the reign of the youngest brother of them all Tsar Kaloyan.

On 14 of April 1205 the armies of Tsar Kaloyan won brilliant victory over the crusaders of the Fourth Crusade near Adrianopolis (present day Edirne in Turkey). The count of Blois was killed. Emperor Baldwin, count of Flanders and Hainaut was taken prisoner and died mysteriously in 1206 in one of the guard towers surrounding Tarnovo, and which since then is called Baldwin Tower. Today you can visit that legendary tower in the old capital of Bulgaria Veliko Tarnovo.

In 1211 the Council of Tarnovo condemns Bogomil movement.

Under the reign of Tsar Ivan Asen II (1218-1241) son of Tsar Asen Bulgarian borders are yet again washed by three seas the Adriatic Sea, the Aegean Sea and the Black Sea, vast territory covering Thrace, Macedonia, Epirus, Wallahia, Moldova and present-day Albania and Central Serbia. At that time the Bulgarian Archbishopric became again Patriarchate (1235).

Following the death of Ivan Asen II, Bulgaria fell into crisis and lost many of its territories. Ivan Alexander is the last Bulgarian Tsar who conducted war with Byzantium. At this time the Ottoman Turks started their expansion in Europe. In 1393 Tarnovo falls into their hands despite desperate resistance from its defenders led by patriarch Evtimiy. The capturing of the Vidin fortress in 1396 finally put an end to the Medieval Bulgarian state.