Asen’s Fortress is a medieval fortress in the Rhodope Mountains, it is located 2-3 km south of Asenovgrad. It is named after the Bulgarian tsar Ivan Asen II. The fortification stands proudly on a high rocky ridge on the left bank of Asenitsa River. According to some researchers, its old name is Petrich.
The first archaeological findings in the area around the fortress date back to the time when Thracians inhabited the area. For centuries, this land and the fortress were in the lands of the Ancient Roman and Byzantine Empire. Because of its strategic position near the Rhodope Mountains, the fortress played a serious role in the wars between the Bulgarian and Byzantine Empire.
The fortress was first mentioned in the statue of the Bachkovo Monastery in the 11th century. During the Third Crusade, the fortification was conquered by the crusaders. Two centuries later, the fortress was under Bulgarian control. In 1231, the Bulgarian tsar Ivan Asen II ordered the fortress to be repaired and additionally fortified. It served as a border fortification against Latin raids, evidence for that is the eight-line wall inscription in the fortress. The fortress was later captured again back by the Byzantines, despite that in 1344 another Bulgarian ruler succeeded in capturing it. Sadly, it was later destroyed and ravaged by the Ottomans in the 14th century. The fortress was abandoned and left in ruins.