Rolf is an English, Norwegian and Danish contracted form of Rudolph. Rudolph originates in Germanic languages and means "legendary wolf". In most European countries it is used in its spelling variant Rudolf, historically borne by multiple kings and rulers. The English version Rudolph was popularized in the 1930s by Robert L. May and his Rudolph the Red-Nosed Reindeer. As a masculine given name it has lost its popularity lately.