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.
[1] In the end of the 13th century, the fortress was the capital of a small short-lived quasi-independent domain[2] ruled by the brothers of Tsar Smilets of Bulgaria, Voysil and Radoslav.
The castle reached its heyday in the last quarter of the 13th century, when under the rule of the Bulgarian nobles (bolyari) Voysil and Radoslav it was the capital of a quasi-independent realm.
The domain comprised the landholdings of the two renegade brothers of Tsar Smilets, which lay between the Balkan Mountains and Sredna Gora, approximately from modern Sliven west to Kopsis.
[3][4] The Anevo Fortress is dominated by its fortified inner city or citadel, surrounded by defensive walls with gates and towers.