Aquitaine (French pronunciation: [a.ki.tɛn], English /ˌækwɪˈteɪn/; Occitan: Aquitània; Basque: Akitania), archaic Guyenne/Guienne (Occitan: Guiana), is one of the 27 regions of France, in the south-western part of metropolitan France, along the Atlantic Ocean and the Pyrenees mountain range on the border with Spain. It is composed of the 5 departments of Dordogne, Lot et Garonne, Pyrénées-Atlantiques, Landes and Gironde. In the Middle Ages Aquitaine was a kingdom and a duchy, whose boundaries fluctuated considerably.

There are traces of human settlement by prehistoric peoples, especially in the Périgord, but the earliest attested inhabitants in the south-west were the Aquitani, who were not proper Celtic people, but more akin to the Iberians (see Gallia Aquitania). Although a number of different languages and dialects were in use in the area during ancient times, it is most likely that the prevailing language of Aquitaine during the late pre-historic to Roman period was an early form of the Basque language. This has been demonstrated by various Aquitanian names and words that were recorded by the Romans, and which are currently easily readable as Basque. Whether this Aquitanian language (Proto-Basque) was a remnant of a Vasconic language group that once extended much farther, or whether it was generally limited to the Aquitaine/Basque region is not currently known. One reason the language of Aquitaine is important is because Basque is the last surviving non-Indo-European language in western Europe and it has had some effect on the languages around it, including Spanish and, to a lesser extent, French.

Eleanor of Aquitaine (French: Aliénor d’Aquitaine; Éléonore de Guyenne) (1122 or 1124 – 1 April 1204) was one of the wealthiest and most powerful women in Western Europe during the High Middle Ages. As well as being Duchess of Aquitaine in her own right, she was queen consort of France (1137–1152) and of England (1154–1189). She was the patroness of such literary figures as Wace, Benoît de Sainte-Maure, and Bernart de Ventadorn.

Eleanor succeeded her father as Duchess of Aquitaine and Countess of Poitiers at the age of fifteen, becoming the most eligible bride in Europe. Three months after her accession, she married Louis VII, son of her guardian, King Louis The Fat. As Queen of France, she participated in the unsuccessful Second Crusade. Soon after the Crusade, Eleanor sought an annulment of her marriage but was rejected by Pope Eugene III. However, after the birth of Alix, another daughter, Louis agreed to an annulment. The marriage was annulled on 11 March 1152, on the grounds of consanguinity within the fourth degree. Their daughters were declared legitimate and custody was awarded to Louis, while Eleanor's lands were restored to her.