The first documented castle was created by Dafydd, brother of Prince Llewelyn ap Gruffydd, for King Edward I of England in 1277 who gave the fort (that was present on the site) to him in return for his treacherous help during the invasion of North Wales that year. Dafydd also had castles at Caergwle and Denbigh.
It was originally known by the Welsh name of Castell Coch yn yr Gwernfor or The Red Castle in the Great Marsh. It consisted of a pentagonal upper bailey that was around 350ft long and 250ft wide with the floor level on the inside higher than the ground outside, which then sloped down to the river below. The other side of the castle was protected by a deep & wide dry moat.