William I of Aquitaine (d. 918), nicknamed the Pious was Count of Auvergne between 886 and 918 and Duke of Aquitaine from 893 to his death, succeeding the Poitiers ruler Ebalus of Aquitaine. William was son of the count Bernard II of Auvergne. He had no sons of his own and was succeeded by a nephew.

In 909, William founded the Benedictine Abbey of Cluny, that would become an important political and religious centre. William required no control over the Abbey and established that Cluny's monks would respond only to the pope.

See also: Dukes of Aquitaine family tree

Preceded by: Ebalus

Duke of Aquitaine

Succeeded by: William II