Paristrion

The territory of the Theme of Paristrion, also known as the Danubian region, was part of Bulgaria under Byzantine rule. It covered the area between the Danube and the Balkan Mountains, including what is now northern Bulgaria. The Theme of Paristrion was established after Emperor Basil II, known as the Bulgar Slayer, conquered north-eastern Bulgaria, generally dated to the early 11th century. A Byzantine governor was appointed, and Drastar (present-day Silistra) became its centre. Paristrion was subjected to various barbarian invasions, including those of the Uzes, Cumans and Pechenegs. It was liberated in 1185.