The Sleeping Dragons of Snowdon Dinas Emrys, Caernarfonshire
The chief Vortigern, who asked the Saxons into England to help him, withdrew from the bother he himself had inflamed, to where the Conwy rises near Snowdon. There he began to build a castle. But what he built by day crumbled by night, and men told him that only the blood of a fatherless child would make his mortar resist darkness. Searches at last found such a child; it was Merlin, whose extraordinary wisdom stayed the murderers' hands. Merlin bade the men dig below the walls, where they found two sleeping Dragons, whose furious quarrels on waking caused the nightly downfall of the building.