Dolwyddelan Castle is believed to have been begun by Llywelyn ab Iowerth in the thirteenth century, and initially consisted of a squat stone keep on a rocky outcrop overlooking the valley of the Afon Ledr. Together with Dolbadarn (NPRN 93541) and Castell Y Bere (NPRN 93719) it dominated the principal routes through Snowdonia, replacing an earlier fortification nearby, Tomen Castle (NPRN 303046).

Following the defeat and death of Llywelyn ap Gruffudd in December 1282, the castle fell to Edward I, who ordered that repairs be undertaken. At this time the keep was heightened and a second rectangular tower was added to provide further accommodation; the English maintained a military presence until 1290 but abandoned the site in favour of more strategic coastal strongholds. Dolwyddelan was occupied by Maredudd ab Ieuan ap Robert at the end of the fifteenth century, who added a further storey to the keep, but later it fell into ruin once again. Major restoration was to take place at the hands of Lord Willougby de Eresby, who restored the eastern tower in the nineteenth century in the Romantic style with false battlements visible today. The remains of the castle consist of two rectangular towers linked by an irregular curtain wall, with ditches and banks on the north-east and south-west sides.

Source: Avent, R. 2004. Dolwyddelan Castle, Dolbadarn Castle & Castell y Bere: Cadw Guide

K Steele, RCAHMW, 4 November 2008