Anevsko kale

The Anevo Fortress or Kopsis is a medieval castle in central Bulgaria, the ruins of which are located some 3 kilometres from the village of Anevo in Sopot Municipality, Plovdiv Province. Constructed in the first half of the 12th century, it lies on a steep hilltop at the southern foot of the Balkan Mountains, not far from the Stryama river. In the end of the 13th century, the fortress was the capital of a small short-lived quasi-independent domain ruled by the brothers of Tsar Smilets of Bulgaria, Voysil and Radoslav.

Source: Wikipedia