One of Eryri’s defining archaeological remains
Tomen y Mur is a Roman fort situated at the base of Mynydd Maentwrog hill, a stone’s throw from Llyn Trawsfynydd. The fort was built by General Gnaeus Julius Agricola in 78AD as part of his campaign to control the Ordovices, a Celtic tribe who opposed Roman rule.
Tomen y Mur through the ages
The landforms around Tomen y Mur suggest that the site once contained a bathhouse, a mansio (a house for visiting officers), a temple, a military amphitheatre and a training field. At one time, four Roman roads met at this point.
The Romans left the fort in 140AD. A millennium later, the Normans erected a castle motte within the walls of Tomen y Mur during a Welsh uprising in 1095.
Tomen y Mur in Folklore
Tomen y Mur is mentioned in legends. This was the home of Lleu Llaw Gyffes and his wife, Blodeuwedd. Their story is told in the fourth branch of the Mabinogi, where Tomen y Mur is referred to as Castell Mur.
A view of Eryri
There are excellent views of Eryri from Tomen y Mur. To the north is the Moelwynion mountain range, to the east is the Arenig range, and to the south is the Rhinogydd range.








