The fortress was built in the place of a Byzantine fortress from the sixth century. It served as an important centre during the Second Bulgarian empire, second only to the capital of Turnovo. It minted coins and in 1235 it became the seat of the Bishopric of Cherven.
The fortress was burned by the invading ottomans in 1388, with most people fleeing to what is today Ruse.
There is also a 3D reconstruction of the town during the 14th century
Thanks for the extra info, interesting!
Iirc this was the first episode of GOT that i saw and started from the beginning right after. I think i remember the tower in the episode.