Venčan Castle

An Ancient (Thracian, Classical, Hellenistic, Roman), Late Antique, and Medieval fortress on a hill northwest of the modern settlement of Venčan (Венчан, also rendered less accurately but more commonly as Venchan). It overlooks a Roman road running in its immediate vicinity. It is poorly preserved, bur numismatic and ceramic remains date to the 5th-7th century and the 11th-14th century. The fortress is mentioned as Vefçan and Vençan in the narrative of the Ottoman conquest in 1388.

https://www.bulgariancastles.com/s-venchan-krepost-venchan/