The medieval castle is situated in the beautiful Rhodope Mountains, just a few kilometers from the town. It is one of the most famous fortresses in Bulgaria. Located on a cliff, it is considered that it was built 2,500 years ago by the Thracians with the aim to serve them as a fort. In the later fort was used by the Romans and Byzantines. Since the late 9th century fortress was used by the Bulgarians, as evidenced objects from this period found during excavations in the area.
The purpose of the fort was to guard the road between Sofia and the Aegean, which is passed through the Rhodopes. Fortification has provided security and land around it is the principal cause of the two settlements near the fort, and current news Pertich Asenovgrad. In the reign of Tsar Ivan Assen II in the fortress were carried out major extensions and improvements. Then Bulgaria was not in good relations with the Latin Empire and the security of the Bulgarian people was under threat. It is believed that the fortress, named after the king, because his management hardness, its preservation and improvement was a priority for the king. Near the fortress is situated one of the most impressive churches in Bulgaria. The church "St. Mary of Petrich" was built in the 8th century. Nowadays the fortress is almost restored and the doors of the castle are open to visitors year round. It is part of the Hundred National Tourist Sites of Bulgaria