Dinas Mawddwy is a village in south-east Gwynedd, north Wales. It lies within the Snowdonia National Park, but just to the east of the main A470, and consequently many visitors pass the village by. Its population is roughly 600. The village marks the junction of the unclassified road to Llanuwchllyn which climbs up through the mountains to cross Bwlch y Groes at its highest point, the second highest road pass in Wales. This minor road also provides the closest access to the mountain Aran Fawddwy.
Mawddwy was the only remaining part of the ancient Kingdom of Powys still ruled by members of the native "royal family" (of Powys Wenwynwyn) after 1309. On the division of the realm in 1293, Mawddwy had been awarded to William de la Pole (of Mawddwy) and his descendants. Eventually the ruling family in Mawddwy would expire in the male line in 1414. The Mawddwy Family who claim descent from William de la Pole still use a version of the traditional Lion of Powys as their arms.
In the 16th century, the Mawddwy area was home to a band of highway robbers and bandits named the ‘Gwylliaid Cochion Mawddwy’ or ‘Gwylliaid y Dugoed’. The Gwylliaid were supposedly the dregs of society, who came to the Dinas Mawddwy area having been excommunicated from their own areas. Some were hanged and others were exiled from the area forever. Two brothers pleaded to be pardoned by the Baron Owain, and his rejection of the plea enraged the Gwylliaid. They were intent on revenge and one night, while the Baron travelled home from Montgomeryshire, the Gwylliaid set traps on the road and shot arrows at the baron and his company. His body was found with thirty arrows attached to it.