Andrew Lang (1844 – 1912) was a Scottish poet, novelist, best known as a collector of folk and fairy tales. "The Frog" is a variant on the Frog Princess. Three brothers are told by their mother to set specific tasks for their sweethearts to complete, to see whether they will make suitable brides. The youngest lad does not know any girls, but a mystery frog proves amazingly adept at all the trials set her by her future mother-in-law.
