against the Milesians, and at their service were malignant sprites—­urtrochta, and “forms, spectres, and great queens” called guidemain (false demons).  The Druids also sent forth mischievous spirits called siabra.  In the Tain there are references to bocanachs, bananaichs, and geniti-glinni, “goblins, eldritch beings, and glen-folk."[567] These are twice called Tuatha De Danann, and this suggests that they were nature-spirits akin to the greater gods.[568] The geniti-glinni would be spirits haunting glen and valley.  They are friendly to Cuchulainn in the Tain, but in the Feast of Bricriu he and other heroes fight and destroy them.[569] In modern Irish belief they are demons of the air, perhaps fallen angels.[570]

Much of this is probably pre-Celtic as well as Celtic, but it held its ground because it was dear to the Celts themselves.  They upheld the aboriginal cults resembling those which, in the lands whence they came, had been native and local with themselves.  Such cults are as old as the world, and when Christianity expelled the worship of the greater gods, younger in growth, the ancient nature worship, dowered with immortal youth,

      “bowed low before the blast
  In patient deep disdain,”

to rise again in vigour.  Preachers, councils, and laws inveighed against it.  The old rites continued to be practised, or survived under a Christian dress and colouring.  They are found in Breton villages, in Highland glens, in Welsh and Cornish valleys, in Irish townships, and only the spread of school-board education, with its materialism and uninviting common sense, is forcing them at last to yield.

The denunciations of these cults throw some light upon them.  Offerings at trees, stones, fountains, and cross-roads, the lighting of fires or candles there, and vows or incantations addressed to them, are forbidden, as is also the worship of trees, groves, stones, rivers, and wells.  The sun and moon are not to be called lords.  Wizardry, and divination, and the leapings and dancings, songs and choruses of the pagans, i.e. their orgiastic cults, are not to be practised.  Tempest-raisers are not to ply their diabolical craft.[571] These denunciations, of course, were not without their effect, and legend told how the spirits of nature were heard bewailing the power of the Christian saints, their mournful cries echoing in wooded hollows, secluded valleys, and shores of lake and river.[572] Their power, though limited, was not annihilated, but the secrecy in which the old cults often continued to be practised gave them a darker colour.  They were identified with the works of the devil, and the spirits of paganism with dark and grisly demons.[573] This culminated in the mediaeval witch persecutions, for witchcraft was in part the old paganism in a new guise.  Yet even that did not annihilate superstition, which still lives and flourishes among the folk, though the actual worship of nature-spirits has now disappeared.