"William X (Guillém X in Occitan) (1099 – 9 April 1137), called the Saint, was Duke of Aquitaine, Duke of Gascony, and Count of Poitou (as William VIII) from 1126 to 1137. He was the son of William IX by his second wife, Philippa of Toulouse.
William was born in Toulouse during the brief period when his parents ruled the capital. His birth is recorded in the Chronicle of Saint-Maixent for the year 1099: Willelmo comiti natus est filius, equivoce Guillelmus vocatus ("a son was born to Count William, named William like himself"). Later that same year, much to Philippa's ire, Duke William IX mortgaged Toulouse to Philippa's cousin, Bertrand of Toulouse, and then left on Crusade." - (en.wikipedia.org 23.01.2021)