Under Ottoman rule, the three major cities each were the center of a sanjak, and were together officially part of Silistra (or Özi) Eyalet although Bender was north of Trajan's Wall and outside of the steppe region. The Nogai Tatar-inhabited steppe, which then acquired the name Budjak, served as a buffer area between these sanjaks and the Principality of Moldavia. Although it was a tributary of the Ottoman Empire, Moldavia was independent in its internal affairs until the start of the Russo-Turkish Wars forced the Ottomans to ensure that the Romanian princes did not switch sides too often.