Aquitaine is one of the 27regions 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 andGironde. In the Middle Ages Aquitaine was a kingdom and a duchy, whose boundaries fluctuated considerably.
After the 843 Treaty of Verdun, the defeat of Pepin II and the death of Charles the Bald, theKingdom of Aquitaine (subsumed in West Francia) ceased to have any relevance and the title of King of Aquitaine took on a nominal value. In 1058, the Duchy of Vasconia (Gascony) and Aquitaine merged under the rule of William VIII, Duke of Aquitaine.
The title "Duke of Aquitaine" was held by the counts of Poitiers from the 10th to the 12th century.