In THE SUMMER QUEEN, Alienor of Aquitaine begins the novel as a bride of 13 years old to the future Louis VII who is 17.
Alienor’s birth date had long been thought to be 1122, making her 15 at her marriage, but research - now more than ten years old suggests that she was actually born in 1124 and thus only 13. The 1124 date is the one that historians now prefer. It's used on the Palais de Justice in Poitiers, which incorporates Alienor's great hall, built after circa 1168.
An early 14th century manuscript, copied from earlier sources says: “In 1136 on the fifth ides of April, which in that year was Good Friday, William count palatine of Poitou and the last duke of Aquitaine, died at Saint James in Galicia, leaving his only daughter named Alienor, aged thirteen years.’
In terms of earlier sources, the text is a pastiche of excerpts from the chronicles of Geoffrey de Vigeois which were composed in Alienor’s own lifetime. Some of the information is accurate, some is not, but Alienor’s birth date is reckoned correct. The errors come when the information stated has been acquired from further afield than Aquitaine.
The scholar who has unravelled the tangle of Eleanor's birth year is Andrew W. Lewis, Prof of history at Southwest Missouri State University. He says:
"For Eleanor of Aquitaine's age, most recent scholars have relied on Alfred Richard, the great modern specialist on the counts of Poitou. But details of this sort were not among Richard's strengths as a scholar. Moreover, he vacillated in his statements on the subject, and his argument is circular. Thus, when speaking of Eleanor's birth, he wrote that it was only from knowing that she was 82 years old when she died, in 1204, that one could place her birthday 1122. Yet when speaking of the death he gave her age as 'about 82 years', while citing no source to that effect."
How did Richards know she was 82 when she died in 1204? There is a primary resource that speaks of her death and which is cited on other occasions - the Chronicae Sancti Albini Andegavensis. When examined by professor Lewis, however, he found that the manuscript did not give any date for her death at all and stated that she died in Poitiers, not at Fontevraud.
Professor Lewis goes on to say that greater confidence can be placed in the genealogical text composed at Limoges because the record contains an early tradition that she was thirteen at the time of her father’s death in April 1137. Lewis is of the opinion that not only would more people at that time, before the passing of generations, have known the facts, but that by canon law women had to be at least 12 years old in order to marry, and the information would have been of practical relevance. It was a deliberate statement that she had attained her majority and important. Most biographers have accepted the Richards’ statement without checking the Chronicae Sancti Albini Andegavensis. chronicle, and therefore calculate the birth date as 1122, based on false secondary sources and that non-existent ‘she died age 82 in 1204' statement.
At the outset of her marriage, then, Alienor was a thirteen year old girl, cast adrift on a sea of uncertainty and facing a future very different to the life she had led thus far. It makes for a fascinating premise to explore in a novel, and one, that as far as I know, has not been used before, other fictions having taken her age at marriage as fifteen.