As Mr. R. U. Sayee has well said: 'It should be clear a priori that fairy lore must have developed as a result of modifications and accretions received in different countries and at many periods, though we must not overlook the part played by tradition in providing a mould that to some extent determines the nature of later additions.' It must also be self-evident that a great deal of confusion has been caused by the assumption that some spirit-types were fairies which in a more definite sense are certainly not of elfin provenance. In some epochs, indeed, Faerie appears to have been regarded as a species of limbo to which all 'pagan' spirits - to say nothing of defeated gods, monsters, and demons - could be banished, along with the personnel of Olympus and the rout of witchcraft. Such types, however, are usually fairly easy of detection.