Tradition claims that this Welsh earth and timber castle which occupies a rocky knoll on the valley bottom was the predecessor to the stone castle at Dolwyddelan. Tomen Castell is said to have been the birthplace of Llywelyn ap Iorwerth, (the Great), the likely builder of the later castle at Dolwyddelan. Both castles controlled a crucial route through southern Snowdonia, and the importance of this site is further attested to by the presence of the Welsh prince's summer pastures or hafotiroedd. Today the mound or motte is covered with trees and vegetation. There are traces of a rectangular tower on the summit.
