 Helig ap Glanawg was said to have lived here when his land was inundated by the sea, which formed the Lavan Sands which lie between the Great Orme's Head and the Menai Strait off the north coast of Gwynedd.The legend states the remains of Llys Helig, said to be his palace but in fact the remnants of a glacial moraine, can be seen at exceptionally low tides, this being near the Conwy channel, about a mile or so off the coast at Penmaenmawr.The earliest known use of the name Llys Helig for this rock formation is the Halliwell Manuscript, published in 1859, which is believed to date to around the beginning of the 17th century, eleven centuries later.