Above: the hill at Dinas Emrys viewed from a distance Below: various views of the castle ruins from the summit of the hill

S trictly speaking, Dinas Emrys doesn't qualify as a medieval Welsh castle, however this is a legendary fortress, believed to be the setting of one of the most enigmatic tales of early British history, left to us by Nennius, a 9th-century writer. The story concerns the early Roman-British-Saxon legends surrounding Vortigern, Merlin, Ambrosius, and the two sleeping dragons (one red and one white) who awoke and fought for the supremacy of Wales. (The red dragon won).

T he fortress sits on a most precipitous rock, which might well be judged the strongest natural fortress in Gwynedd. The footings of a rectangular stone tower now stand on a rock above a medieval cistern. It's construction is likely to belong to the reign of Llywelyn ap Iorwerth (d.1240), the most active castle builder among the Welsh princes.

D inas Emrys is on A498 1.2m NE of Beddgelert. Owing to vulnerability of the remains and difficulty of access, all visitors must first contact NT Warden at Beddgelert. A way-marked route (45 mins attractive walk) brings you up the summit of the NE ridge. The western ramparts are fragile and dangerous; exploration is not advised.

A Guide to Ancient and Historic Wales: Gwynedd, Frances Lynch, Cadw: Welsh Historic Monuments, London, 1995.