Kaliakra is a long and narrow headland in the Southern Dobruja region of the northern Bulgarian Black Sea Coast, located 12 km east of Kavarna and 60 km northeast of Varna. The coast is steep with vertical cliffs reaching 70 m down to the sea.
In 4th century BC a settlement called Tirrisis was founded bearing the name of a local Thracian tribe. In Roman times the fortress rapidly grew – lots of public buildings and facilities were built. There were plumbing system, churches, public baths (Roman thermes), fortification walls most of which can still be seen today. The cape became a strong Bulgarian fortress and flourished in the second half of the 14th century as a capital of the Dobrotitsa dukedom. It was a powerful medieval town minting its own coins. The fortress declined when it was conquered by The Ottoman Empire.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.