Born in Angers she was the eldest child of Count Fulk IV of Anjou but the only one born by his first wife, Hildegarde of Beaugency. Having lost her mother in 1070, at only two years of age, she received a good education and grew to be pious and concerned about religious reform, especially the struggle against the secular appropriation of church property. She was also noted for her beauty in her youth.
Duchess of Aquitaine
It has long been presumed that, in 1089, her marriage was arranged to the young Duke and poet, William IX of Aquitaine. However, this union proved a dismal failure. Her husband was a voracious philanderer, whose affairs infuriated his wife. She suffered from severe mood swings, vacillating between vivacity and sullenness, and would nag her husband. She also had a habit of retiring in bad temper to a cloister after an argument, cutting off all contact with the outside world, before suddenly making a reappearance in the court as if her absence had never occurred. Such behavior, coupled with her failure to conceive a child, led William to send her back to her father and have the marriage dissolved in 1091. Her behavior during her marriage to the Duke has been described by both Marion Meade and Alison Weir as schizophrenic, with Weir adding a suggestion of manic depression. However, Ruth Harvey's 1993 critical investigation shows the assumption of William's marriage to Ermengarde to be based largely on an error in a nineteenth-century secondary source and it is highly likely that Philippa of Toulouse was William's only wife. Further research has found the claim that William was married to "Hermingerda", daughter of Fulk IV of Anjou is based on the very unreliable chronicle of William of Tyre, written between 1169 and 1187, more than 70 years after the events in question would have taken place. Tyre erroneously identifies Ermengarde's mother as Bertrand of Montfort, the sister of Amalricus de Montfort when her mother was in fact Audearde or Hildegarde of Beaugency. Tyre's chronicle lacks any contemporary corroboration, no primary text ever mentions a marriage between William and Ermengarde. It is therefore not only improbable that William married Ermengarde, it is likely that Ermengarde - at least as a wife of William - never existed. But Stephen Philp, poet and mediaeval historian, has counter-argued that, on the basis of pure logic, even if we accept that Ermengarde never married Duke William IX, this has no bearing on whether she actually existed or not. Ermengarde's existence is indeed supported by the correction of the name of her mother. Moreover, several sources give colourful accounts of the marriage and its aftermath, and her later marriage, so there is no good reason to doubt it.
Duchess and regent of Brittany
In 1093, her father married her to Duke Alan IV of Brittany, probably to secure an alliance against Normandy, then controlled by William the Conqueror’s son, Robert Curthose. The union produced three children: the future Duke Conan III, Hawise and Geoffrey. Her husband left for Palestine in 1096 to take part in the First Crusade and she served as Regent of the Duchy from then until 1101. She spent little time in Rennes or the west of Brittany, preferring Nantes and the Saumur region. Influenced by Robert of Arbrissel, she approved the expansion of the abbey at Fontevraud, to which she withdrew on two occasions. An admirer of Saint Bernard of Clairvaux, she favored the creation of Cistercian abbeys. She was also a benefactor of the monastery of Buzay, near Nantes. Alan IV, an unpopular ruler, was forced to abdicated in favor of his son in 1112, and he and Ermengarde were separated after this.
Later years
By 1116 Ermengarde was living in Fontevrault Abbey, where she reputedly became a friend of her first husband's second wife, Philippa of Toulouse. In 1118 after the death of Philippa, Ermengarde decided to avenge her deceased friend. She went south from Fontevrault to the court of her former husband, Duke William of Aquitaine, where she demanded to be recognized as the rightful Duchess. William ignored this remarkable request. Accordingly, in October 1119, she suddenly appeared at the Council of Reims, being held by Pope Calixtus II, demanding that the Pope excommunicate William, oust his mistress from the ducal palace, and restore Ermengarde to her rightful place as the Duchess of Aquitaine. The Pope "declined to accommodate her"; however, Ermengarde continued to trouble William for several years afterwards.
Death
Ermengarde at one point went on Crusade to Palestine; she returned ten years later, and some historians believe her life ended in Jerusalem at the convent of Saint Anne. But obituary lists at Redon Abbey record a date of death in 1146 in Redon where her second husband, Alan IV was buried. It is believed that she died a nun. The contradictions about her death and the records of her burial maybe indicated that in fact she died in Jerusalem, and that her body was subsequently transferred to Redon.
