Ruysbroeck, Willem van, b 1215 in Rubrouck, France, d ca 1295. Flemish Franciscan friar and diplomat. He was sent by King Louis IX of France in 1253–5 on an informal mission to the camp of Batu Khan on the Mongolian plain. His account of the journey, republished in 1900 as The Journey of William of Rubruck to the Eastern Parts of the World, 1253–55, provides a valuable description of the Mongol Empire and includes passages describing life in Kyivan Rus’ in this period.

[This article originally appeared in the Encyclopedia of Ukraine, vol. 4 (1993).]