 The sea level was low enough around 1600 AD to make the claims of Sir John Wynne of Gwydir feasible.The earliest known use of the name Llys Helig for this rock formation is the Halliwell Manuscript which is believed to date to around the beginning of the 17th century, eleven centuries later.Legends developed about it suggesting that it was the palace of Prince Helig ap Glanawg ("also spelled" Glannog) who lived in the 6th century, and whose sons established a number of churches in the area.