The region where Vlachs predominantly live later on was part of the Second Bulgarian Empire, whose first rulers, the Asens, are considered Vlach. King Stephen Uroš II Milutin of Serbia had most of Timok after his conquering of rival King Stephen Dragutin's lands. The chroniclers of the crusaders describe meeting Vlachs in the 12th and 13th century in various parts of modern Serbia. Serbian documents from the 13th and 14th century mention Vlachs, including Emperor Dušan the Mighty, in his prohibition of intermarriage between Serbs and Vlachs. 14th and 15th century Romanian (Wallachian) rulers built churches in NE Serbia. 15th century Turkish tax records ("defters") list Vlachs in the region of Braničevo in NE Serbia, near the ancient Roman municipium and colonia of Viminacium.