After the Anglo Norman Conquest the name Garth Celyn continued in local use but was not used by the English administration. Instead the settlement Aber Garth Celyn adjacent to the royal home became officially known by the administrators simply as Aber, ‘Estuary’ with its identity removed; later more descriptively as Aber Gwyn Gregyn, ‘Estuary of the White Shells’.

On 18 January 1283, Dolwyddelan Castle was occupied by the army of invasion (PRO. E101/359/9) and immediately munitioned to provide a base in the Lledr valley. At Edward’s command raiding parties were sent out into the mountains of Snowdonia.

On 22 June 1283, Prince Dafydd ap Gruffudd, heir to the Principality, was captured, his hiding place at the foot of Bera in the uplands above Aber Garth Celyn, betrayed. (E101/3/30) Dafydd, seriously wounded ‘graviter vulneratus’ in the struggle was taken that same night to Edward at Rhuddlan. (Cotton Vesp. B xi, f. 30) Wales was plundered, and Edward’s trophies taken across the border into England.

The matrices of the personal seals of Prince Llywelyn, his wife Eleanor de Montfort, daughter of Earl Simon, and his brother Prince Dafydd were seized and placed in the royal Wardrobe. Edward ordered that these also were to be melted down and the silver used to craft a chalice, which he intended to present to the new Cistercian foundation of Vale Royal abbey in Cheshire.