Westphalia is a former Prussian province of western Germany. Westphalia, or Westfalen in German, means western plain. It lies just east of the Netherlands. Westphalia once belonged to the Duchy of Saxony. In the late 1100’s, the name Westphalia was given to a region ruled by the archbishop of Cologne. Prussia gained control of the area at the Congress of Vienna (1814-1815). In 1946, Westphalia became part of the German state of North Rhine-Westphalia.