Guyenne or Guienne is an old French province that corresponds roughly to the Aquitania Secunda of the Romans and the archbishopric of Bordeaux.

In the twelfth century ithad formed with Gascony the duchy of Aquitaine, which had passed under the dominion of the kings of England by the marriage of Eleanor of Aquitaine to Henry II.

In the thirteenth century, through the conquests of Philip Augustus, Louis VIII and Louis IX, it was confined within the narrower limits fixed by the treaty of Paris (1259).

It is at this point that Guyenne became distinct from Aquitaine.

It then comprised the Bordelais (the old countship of Bordeaux), the Bazadais, part of Périgord, Limousin, Quercy and Rouergue, and the Agenais ceded by Philip III to Edward I in 1279.

Still united with Gascony, it formed a duchy extending from the Charente to the Pyrenees.

This duchy was held as a fief on the terms of homage to the French kings, and both in 1296 and 1324 it had been confiscated by the kings of France on the ground that there had been a failure in the feudal duties.

At the treaty of Brétigny (1360), King Edward III acquires the full sovereignty of the duchy of Guyenne, together with Aunis, Saintonge, Angoumois and Poitou.

The victories of the Frenchmen Bertrand du Guesclin and Gaston Phœbus restore the duchy soon after to its thirteenth-century limits.

In 1451 it is conquered and finally united to the French crown by Charles VII.