Demir Baba Teke is a 16th-century Alevi mausoleum (türbe) near the village of Sveshtari. It is thought to be the resting place of Demir Baba, a 16th-century Alevi saint. The tomb itself is a heptagonal building constructed out of local sandstone. It has a lower rectangular antechamber and is covered by a hemispherical dome 11 metres (36 ft) in height. Demir Baba's grave lies in the middle of the heptagonal inner premises. Constructed out of bricks and wood, the sarcophagus is 3.74 metres in length and is positioned with the saint's head pointing southwest. The sarcophagus is usually entirely covered by gifts and is only rarely displayed to Alevi pilgrims.
The mausoleum is thought to have been constructed in the 16th century on what was probably an ancient Thracian holy site from the 4th century BC. A cult complex (tekke) gradually emerged around the türbe. This included a holy spring, a mosque that was mentioned by travellers in the 18th and 19th centuries but was then destroyed, and a wooden public kitchen (imaret) which was pulled down in 1976 due to its deteriorating condition. The tekke features that have survived until today are the mausoleum, the holy spring, a residential building and a low stone fence surrounding the complex. A small exhibition in the residential building explains the story of the Alevis and Demir Baba himself.
Demir Baba Teke was proclaimed a monument of culture of local importance in 1970 by the government of the then-People's Republic of Bulgaria. The mausoleum was renovated in 1991–1994: the decaying wooden floor was replaced with a new one and the building's interior decorative elements (including the 19th-century murals) were reconstructed.
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.