The Roman Wall is the popular but incorrect name for an early Ottoman-era architectural monument in Sofia, the capital of Bulgaria. Part of a 16th or 17th-century Islamic religious building, it now stands in the middle of a small marketplace in the Lozenets neighbourhood.
The Roman Wall is a rectangular structure of straight rows of bricks and stones. It exhibits a characteristic Ottoman construction method of surrounding the large cut stones with sets of bricks. The wall is situated with an east–west orientation and features two windows, with a mihrab niche in between. A notched brick cornice decorates the top of the wall.
The Roman Wall was built in the 16th or 17th century, the time of the Ottoman rule of Bulgaria. The wall's exact purpose is unclear, though it is agreed that it performed an Islamic religious function. It may either be the preserved part of an eminent Ottoman Turk's tomb, or it may have formed part of a namazgâh, an open-air religious structure where the imam would perform a prayer for those embarking on the Hajj.
In the late 19th century, after the reestablishment of the Principality of Bulgaria in 1878, the Old Wall remained as a lone marker in the abandoned Turkish graveyard. In 1957, the wall underwent a reconstruction and was enlisted as a monument of culture.
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.