"The Sidhe cannot make themselves visible to all. They are shape-changers; they can grow small or grow large, they can take what shape they choose; they appear as men or women wearing clothes of many colours, of today or of some old forgotten fashion, or they are seen as bird or beast, or as a barrel or a flock of wool. They go by us in a cloud of dust; they are as many as the blades of grass. They are everywhere; their home is in the forths, the lisses, the ancient round grass-grown mounds. There are thorn-bushes they gather near and protect; if they have a mind for a house like our own they will build it up in a moment. They will remake a stone castle, battered by Cromwell's men if it takes their fancy, filling it with noise and lights. Their own country is Tir-nan-Og--the Country of the Young..."