The earliest archaeological findings date back from the time of the Thracians, the area of the fortress has also been inhabited during the Ancient Roman and Early Byzantine period.
The fortress was conquered by the armies of the Third Crusade.
The Asen’s Fortress was considerably renovated in the 13th century during the rule of Bulgarian tsar Ivan Asen II to serve as a border fortification against Latin raids, as shown by an eight-line wall inscription.
The foundations of the fortified walls (the outer ones being 2.9 m thick and preserved up to a height of 3 m, originally 9 – 12 m high), a feudal castle, 30 rooms and 3 water repositories have been excavated from this period.
Taken by the Byzantines after Ivan Asen II’s death, the Asen Fortress was once again in Bulgarian hands at the time of Ivan Alexandar in 1344 only to be conquered and destroyed by the Ottomans during their rule of Bulgaria.