William VIII ( – 25 September 1086), born Guy-Geoffrey (''Gui-Geoffroi''), was duke of Gascony (1052–1086), and then duke of Aquitaine and count of Poitiers (as William VI) between 1058 and 1086, succeeding his brother William VII (Pierre-Guillaume).

Life

Guy-Geoffroy was the youngest son of William V of Aquitaine by his third wife Agnes of Burgundy. He was the brother-in-law of

Henry III, Holy Roman Emperor Henry III (28 October 1016 – 5 October 1056), called the Black or the Pious, was Holy Roman Emperor from 1046 until his death in 1056. A member of the Salian dynasty, he was the eldest son of Conrad II and Gisela of Swabia. Henry was raised by ...

who had married his sister,

Agnes de Poitou Agnes of Poitou ( – 14 December 1077), was the queen of Germany from 1043 and empress of the Holy Roman Empire from 1046 until 1056 as the wife of Emperor Henry III. From 1056 to 1061, she ruled the Holy Roman Empire as regent during the m ...

. He became Duke of Gascony in 1052 during his older brother William VII's rule. Gascony had come to Aquitanian rule through William V's marriage to Prisca (a.k.a. Brisce) of Gascony, the sister of Duke

Sans VI Guilhem of Gascony Sancho VI William (Basque: ''Antso Gilen'', French: ''Sanche Guillaume'', Gascon: ''Sans Guilhem'', Spanish: ''Sancho Guillén'') (died 4 October 1032) was the Duke of Gascony from 1009 to his death. His reign is most notable for the renewal of Ga ...

. William VIII was one of the leaders of the allied army called to help Ramiro I of Aragon in the

Siege of Barbastro The crusade of Barbastro (also known as the siege of Barbastro or battle of Barbastro) was an international expedition, sanctioned by Pope Alexander II, to take the Spain, Spanish city of Barbastro, then part of the Banu Hud, Hudid Taifa of Léri ...

(1064). This expedition was the first campaign organized by the papacy, namely

Pope Alexander II Pope Alexander II (1010/1015 – 21 April 1073), born Anselm of Baggio, was the head of the Roman Catholic Church and ruler of the Papal States from 1061 to his death in 1073. Born in Milan, Anselm was deeply involved in the Pataria refor ...

, against a Muslim town and stronghold in the Emirate of Zaragoza, and the precursor of the later

Crusades The Crusades were a series of religious wars initiated, supported, and sometimes directed by the Latin Church in the medieval period. The best known of these Crusades are those to the Holy Land in the period between 1095 and 1291 that were in ...

movement. Aragon and its allies conquered the city, killed and enslaved its inhabitants and collected an important booty. However, Aragon lost the city again in the following years. During William VIII'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.

Marriage and children

William married three times and had at least five children. After he divorced his first two wives, the first due to infertility, he married a third time to a much younger woman who was also his cousin

Robert I of Burgundy Robert I (1011 – 21 March 1076), known as Robert the Old and " fro, Tête-Hardi, lit=the Headstrong", was Duke of Burgundy from 1032 to his death. Robert was the son of King Robert II of France and Constance of Arles. His brother was Henry I ...

's daughter. This marriage produced a son, but William VIII had to visit Rome in the early 1070s to persuade the pope to recognize his children from his third marriage as legitimate. *First wife: of Périgord, daughter of Count Aldabert II of Périgord (divorced November 1058), no children. She became a nun at Saintes. *Second wife: Matoeda (divorced May 1068) # Agnes, married

Alfonso VI of Castile Alphons (Latinized ''Alphonsus'', ''Adelphonsus'', or ''Adefonsus'') is a male given name recorded from the 8th century (Alfonso I of Asturias, r. 739–757) in the Christian successor states of the Visigothic kingdom in the Iberian peninsula. ...

*Third wife:

Hildegarde of Burgundy Hildegarde of Burgundy (–1104) was a French noble, Duchess consort of Gascony and Aquitaine by marriage to William VIII, Duke of Aquitaine. She was the only daughter of Robert I, Duke of Burgundy with his second wife, Ermengarde of Anjou. ...

(daughter of duke

) # Agnes (died 1097), married

Peter I of Aragon Peter I ( es, Pedro, an, Pero, eu, Petri; 1068 - 1104) was King of Aragon and also Pamplona from 1094 until his death in 1104. Peter was the eldest son of Sancho Ramírez, from whom he inherited the crowns of Aragon and Pamplona, and Isabella o ...

Life

Marriage and children

Notes

References

Sources

See also