Humanities › History & Culture Petronilla: Learn About the Famous Sibling of Eleanor of Aquitaine Share Flipboard Email Print History & Culture Women's History History Of Feminism Important Figures Key Events Women's Suffrage Women & War Laws & Womens Rights Feminism & Pop Culture Feminist Texts American History African American History African History Ancient History and Culture Asian History European History Genealogy Inventions Latin American History Medieval & Renaissance History Military History The 20th Century View More By Jone Johnson Lewis Women's History Writer B.A., Mundelein College M.Div., Meadville/Lombard Theological School Jone Johnson Lewis is a women's history writer who has been involved with the women's movement since the late 1960s. She is a former faculty member of the Humanist Institute. our editorial process Jone Johnson Lewis Updated May 20, 2019 Eleanor of Aquitaine inherited the right to rule Aquitaine; learn about her lief and family below. 01 of 02 Siblings of Eleanor of Aquitaine Ann Ronan Pictures/Print Collector/Getty Images Eleanor of Aquitaine had two full siblings, children of her father, William X of Aquitaine and his wife, Aenor de Châtellerault. Aenor was the daughter of Dangerossa, mistress of William X’s father William IX. Aenor’s father was Dangerossa’s first husband, Aimery. William X was the son of William IX and his first wife, Philippa. When William IX returned from a crusade, he put aside Philippa and lived openly with Dangerossa. Eleanor’s full siblings were Petronilla and William Aigret. William and his mother Aenor de Châtellerault died in 1130 when William was four. William X also had a son by a mistress, also named William, a half-sibling of Eleanor of Aquitaine. 02 of 02 Petronilla of Aquitaine’s Children National Museum & Galleries of Wales Enterprises Limited/Heritage Images/Getty Images Petronilla, called Alix after her marriage, married Raoul (Ralph) I of Vermandois. He was married when they met. He was a grandson of Henry I of France and a cousin of Louis VII, first husband of Petronilla's sister Eleanor of Aquitaine. Their marriage was first declared illegitimate by Pope Innocent II and later accepted by Pope Celestine II. Petronilla and Raoul had three children before they divorced in 1151. Raoul then married into the Flanders royal family and married his daughters and son into the Flanders nobility as well. Petronilla was a companion to her sister Eleanor for many years, including when Eleanor was held captive by her husband Henry II. Petronilla died sometime after 1189. Petronilla’s children were first cousins of the French and English royal children of Eleanor of Aquitaine. The only grandchild of Petronilla of Aquitaine died in early childhood. 1. Elisabeth, Countess of Vermandois (1143 – 1183): after her father died, her older half-brother (by Raoul’s first wife, Eleonore of Blois) Hugh inherited Vermandois; then her brother Raoul succeeded (died 1167) and finally Elisabeth became co-ruler with her husband, Philip of Flanders (1159 – 1183). Philip's mother was Sibylla of Anjou, whose father had become King of Jerusalem through marriage; Sibylla had served as regent for her father at times. Elisabeth's active co-rule lasted until 1175 when Philip had Elisabeth’s lover, Walter de Fontaines, killed. Philip designated his sister and her husband as his heirs. His sister, Margaret, was the widow of Elisabeth's brother Raoul, though she had after Raoul's death remarried. Elisabeth's sister Eleanor had to appeal to the King of France to regain control of Vermandois. 2. Raoul (Ralph) II, Count of Vermandois (1145 – 1167): in 1160 he married Margaret I, Countess of Flanders. She was the daughter of Sibylla of Anjou and Thierry, Count of Flanders, and the heir of her brother, Philip of Flanders, who was married to Raoul's sister Elisabeth. Raoul died of leprosy in 1167 without having had children. His widow remarried and their children married into royalty. His sister Elisabeth and her husband Philip became co-rulers of Vermandois. 3. Eleanor of Vermandois (1148/49 – 1213): married four times, had no surviving children. She ruled Vermandois from 1192 to 1213 in her own right, after both her brother and her sister’s husband died, though she had to appeal to the French king to keep Vermandois from being inherited by her brother-in-law’s sister and her husband. Her marriages: 1162 - 1163: Godfrey of Hainaut, Count of Ostervant and heir to Hainaut. He died just before an intended voyage to Palestine.1165 – 1168: William IV, Count of Nevers. He died on crusade at Acre.1171 – 1173. Matthew, Count of Boulogne. She was his second wife. Their daughter died in early childhood. He died at the siege of Trenton.1175 – 1192: Matthew III, Count of Beaumont. They divorced.