Berthold IV, Duke of Zähringen (b.c 1125)
Berthold IV, Duke of Zähringen (c. 1125 – 8 December 1186) was a Duke of Zähringen and Rector of Burgundy. He was the son of Conrad I, Duke of Zähringen and Clementia of Luxembourg-Namur. He founded numerous cities, including Fribourg.