The Duchy of Aquitaine was a historical fiefdom in western, central, and southern areas of present-day France to the south of the river Loire, although its extent, as well as its name, fluctuated greatly over the centuries, at times comprising much of what is now southwestern France (Gascony) and central France.

In medieval historiography, West Francia or the Kingdom of the West Franks constitutes the initial stage of the Kingdom of France and extends from the year 843, from the Treaty of Verdun, to 987, the beginning of the Capetian dynasty. It was created from the division of the Carolingian Empire following the death of Louis the Pious, with its neighbor East Francia eventually evolving into the Kingdom of Germany.