Guillem IV de Borgonya

William III of Mâcon (1088–1156), also known as William IV of Burgundy, was count of Mâcon (1102–1156), count of Auxonne (1127–1156), count of Vienne (1148–1156) and regent of the county of Burgundy (1148–1156). He was a younger son of Stephen I, Count of Burgundy, and of Beatrice of Lorraine. After the death of his brother, Renaud III, he took control of the county of Burgundy in the name of his niece Beatrice. He was recognized as count by the emperor Frederick Barbarossa by 1152. He died in 1156 while on Crusade in the Holy Land, and Frederick married Beatrice and took over the county.