Mosynopolis , of which only ruins now remain in Greek Thrace, was a city in the Roman province of Rhodope, which was known until the 9th century as Maximianopolis. The city of Maximianopolis appears in written sources from the 4th century on. Its fortifications were renewed by Byzantine emperor Justinian I, and it was later a base for operations by Emperor Basil II in his wars against the Bulgarians.
In the 11th century, the city was the center of a district (bandon) in the theme of Boleron, and Anna Komnene reports in her Alexiad that there were many Manichaeans living in Mosynopolis in the late 11th/early 12th centuries. The town was captured in 1185 by the Normans, while the monk Ephrem says that the city was captured in 1190 by Frederick I, Holy Roman Emperor. The Battle of Messinopolis, in which the Bulgarians defeated Boniface I, Marquess of Montferrat, took place nearby in 1207, and was speedily followed by the destruction of Mosynopolis by Tsar Kaloyan of Bulgaria.
Bishops of Maximianopolis in Rhodope were present at the 5th and 6th-century ecumenical councils of Ephesus (431), Chalcedon (451), and Constantinople II (553) and in another council of 459. From the 7th to the 9th centuries, the see is referred to as archiepiscopal, giving it autocephalous status.
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.