William VIII of Aquitaine
William VIII of Aquitaine, (Guy-Guillaume in French) (1025 ÃÂ September 25 1086) was the Duke of Aquitaine and Count of Poitiers between 1058 and 1086, following his brother William VII (Pierre-Guillaume). He became the Duke of Gascony in 1052, during his elder brother's rule. Gascony, henceforward known as Guyenne, had come to Aquitanian rule through William's fatherÃÂs marriage to Sancha, the heiress of the house.William was one of the leaders of the allied army, called to help Ramiro I of Aragon in the siege of Barbastro (1064). This expedition was the first campaign organized by the papacy, namely Pope Alexander II, against a Muslim city, and the precursor of the later Crusades movement. Aragon and its allies conquered the city, killed its inhabitants and collected an important booty. However, Aragon lost the city again in the following years. During William's rule, the alliance with the southern kingdoms of modern Spain was a political priority as shown by the marriage of all his daughters to Iberian kings.
William was the youngest son of William V of Aquitaine by his wife Agnes of Burgundy. He was the brother-in-law of Henry III, Holy Roman Emperor who had married his sister, Agnes de Poitou. He married three times and had at least five children:
- First wife: Anne of Perigord (divorced 1058)
- Agnes (1052-1078), married Alfonso VI of Castile
- Second wife: Matilda of La Merche (divorced 1068), no children
- Third wife: Hildegard of Burgundy (daughter of duke Robert I of Burgundy)
- Beatrice (d.1110), married to Alfonso VI of Castile
- Hugh (d.1126)
- Agnes (d.1097), married Peter I of Aragon
- William IX of Aquitaine, his heir
| Preceded by: William VII | Duke of Aquitaine | Succeeded by: William IX |
| Count of Poitiers |