His specific origins are unclear; according to the seventeenth-century genealogist Père Anselme, he was the son of Ursio I, viscount of Melun, a town about 50 kilometres outside Paris in the Brie region of the French Vexin, which was later known as the Île-de-France.
[3] According to twelfth-century monk Guibert of Nogent, William was "powerful in words, but less so in action...a man who set out to do things too great for him.
"[4] William was a member of the French contingent which marched into Spain in 1087 to assist Alfonso VI of Castile with the siege of Tudela against the Almoravids.
"[7] William's actions in Spain may have been the inspiration for the character of Ganelon in the Chanson de Roland, which was possibly written in the early twelfth-century, based on similar events that had occurred during the reign of Charlemagne centuries earlier.
[8] In France, Guibert says he engaged in petty warfare against other nobles and "criminal looting" of the countryside, in contravention of the Peace and Truce of God.
They travelled back towards Constantinople, but on the way met Emperor Alexius I Comnenus, who was advancing to Antioch with a relief army.
[20] William's actions at the Siege of Antioch are known from the Gesta Francorum, an anonymous chronicle written by an Italo-Norman eyewitness.
According to Robert, William "acquired the name of 'Carpenter' because nobody wanted to take him on in battle—there was no breastplate, helmet or shield which could withstand the shattering impact of his lance or sword.
[23] Edward Gibbon, apparently misunderstanding Guibert, thought the nickname came "from the weighty strokes of his axe".