Who married Henry I, Count of Vianden?

Henry I (c.1200–1252) was the hereditary Count of Vianden in the Holy Roman Empire, from 1210 and, through his wife, Marquis of Namur from 1229.

Margaret de Courtenay, Marchioness of Namur (c. 1194 – Marienthal, 17 July 1270) was ruling Marchioness of Namur, from 1229 to 1237. She was the daughter of Peter of Courtenay (d. 1219), Latin Emperor of Constantinople (1216-1219) and Yolanda of Flanders (d. 1219). By her second marriage, to Henry I, Count of Vianden (d. 1252), Margaret was Countess-consort of Vianden.