From French Adèle, an ancient name popular in medieval Europe because of the fame of a 7th-century saint, a daughter of the Frankish king Dagobert II. It is of Germanic origin, from adal ‘noble’ (a short form of a two-element name such as Adelheid; see Adelaide). It was the name of William the Conqueror's youngest daughter (c.1062–1137), who became the wife of Stephen of Blois. However, it died out in England in the later Middle Ages. It was revived in the 19th century, being the name of a character in Johann Strauss's opera Die Fledermaus. Its popularity was further reinforced in the 1930s as the name of a character in the novels of Dornford Yates.