William I (1020 – 12 November 1087), called the Great (le Grand or Tête Hardie, "the Stubborn"), was Count of Burgundy from 1057 to 1087 and Mâcon from 1078 to 1087. He was a son of Reginald I, Count of Burgundy and Alice of Normandy, daughter of Richard II, Duke of Normandy.^[1] William was the father of several notable children, including Pope Callixtus II.

In 1057, William succeeded his father and reigned over a territory larger than that of the Franche-Comté itself. In 1087, he died in Besançon, Prince-Archbishopric of Besançon, Holy Roman Empire—an independent city within the County of Burgundy. He was buried in Besançon's Cathedral of St John.

William married a woman named Stephanie [fr] (a.k.a. Etiennette).^[2]

Children of Stephanie (order uncertain):

• Renaud II, William's successor; died on First Crusade^[3]
• Stephen I, successor to Renaud II;^[4] died on the Crusade of 1101^[3]
• Raymond of Burgundy, who married Urraca of León and Castile and thus was given the government of Galicia (Spain)^[4]
• Sibylla of Burgundy, Duchess of Burgundy^[5]
• Gisela of Burgundy, Marchioness of Montferrat^[5]
• Clementia married Robert II, Count of Flanders^[6] and was regent during his absence. She married, secondly, Godfrey I, Count of Leuven^[5]
• Guy of Vienne, elected pope, in 1119 at the Abbey of Cluny, as Callixtus II^[3]
• William
• Eudes
• Hugh III [fr], Archbishop of Besançon^[3]
• Stephanie married Lambert, lord of Peyrins (brother of Adhemar of Le Puy)
• Ermentrude, married (in 1065) Theodoric I, Count of Montbéliard^[5]