Known locally as ‘Owain Glyndŵr’s Mount’, it is actually the remains of a 12th century castle motte built to command the route through the Dee Valley.
Yr enw a roddir iddi'n lleol yw 'Tomen Owain Glyndŵr', adfeilion mwnt castell o'r 12fed ganrif ydyw, a adeiladwyd i arwain y llwybr drwy Ddyffryn Dyfrdwy.