William of Gellone was a ninth-century military leader and the second Duke of Toulouse. A kinsman of Charlemagne, he served the Frankish court and led significant military campaigns against Umayyad forces in the region. In 804, he established the abbey of Gellone, which later became the site of his monastic retirement. He is recognized as a saint in several Christian traditions and is celebrated for his role in both historical defense and religious foundation in southern France.