William I of Baux (Occitan: Guilhèm dei Bauç, archaic Guillem or Guilhem dels Baus, French: Guillaume des Baux or du Baus, Latin: Guillelmus de Balcio; c. 1155 – June 1218) was the Prince of Orange from 1182 until his death.
William was the son of Bertrand I of Baux [fr], the first Prince of Orange and a major patron of Occitan poetry, and Tibors de Sarenom, a sister of Raimbaut d'Aurenga and herself a trobairitz.
The merchant subsequently counterfeited the royal seal and used it to lure William to his (unnamed) city with promises of rewards.
This event inspired a cobla from the troubadour Raimbaut de Vaqueiras, who nicknamed William Engles ("the Englishman", for unknown reasons).
William also had a daughter named Tibors who married Giraud III Amic, lord of Thor de Châteauneuf.