The Balts east of a slight ridge at Viļaka were gradually Russified from the 15–16th centuries, but the philologists August Johann Gottfried Bielenstein and Kārlis Mīlenbahs, conducting linguistic field research in the area in the late 19th and early 20th century, found that many people, called "Russian Latvians" by the local Russians, still spoke the High Latvian dialect.
Major cities, towns and castles of Wenden Voivodeship were: Kies, Ryga, Kokenhausen, Kircholm, Dyneburg, Rzezyca, Marienhaus, Schwanenburg, Lucyn, Krustpils.