Tomen y Mur, Snowdonia National Park

Tomen y Mur is a Roman fort in an isolated rural location near Trawsfynydd, in the Snowdonia National Park. It sits on high ground with panoramic views over important communication routes. Built in timber and earth following the hard-won conquest of north Wales in AD 77, it was refashioned as a smaller stone-walled fort in about AD 120.

Today, the fort is under pasture. It is on private land, with public access through an agreement between the landowner and the Snowdonia National Park Authority (SNPA). The outlines of its two phases can be clearly read on the ground as banked and ditched perimeter defences. Geophysical survey has revealed details of its internal layout and identified a vicus (non-military settlement) outside the north-east gate. The fort is important because many different elements of its contemporary landscape survive, including a small amphitheatre (ludus), substantial parade ground, bathhouse, mansio (guest house for officials), bridge abutments, and a network of leats feeding water to the fort.

Tomen y Mur was abandoned by AD 130, but had lasting political and cultural significance into the medieval period. In the famous Welsh Mabinogi legends, the site is known as Mur Castell (literally ‘Castle Walls’), which indicates that the tale pre-dates the late 11th-century motte (tomen in Welsh) raised by the Normans during unsuccessful campaigning against the Princes of Gwynedd.

Recently, Aerial-Cam has produced high-quality aerial imagery and a detailed digital terrain model for the SNPA as a basis for condition-monitoring and interpretation. Landscape models in 3D have been uploaded to the Sketchfab website and can be seen at https://sketchfab.com/ aerial-cam/collections/tomen-y-mur.