Craigie was also fluent in Icelandic and an expert in the field of rímur. He made many valuable contributions in that field. His interest was awakened by a winter of study in Copenhagen, then the centre of Norse philology. He compiled the complete Oxford edition of Hans Christian Andersen's fairy tales, with previously untranslated tales being supplied by his wife. He befriended many of the great Norse philologists of the time and came across séra Einar Guðmundsson's seventeenth-century Skotlands rímur, dealing with the Gowrie Conspiracy. Being a Scotsman himself, there was no way back, and he continued research in that field till the end of his life.