Aydon Castle was originally a late 13th century stone manor house, founded by Hugh de Reymes. In 1305, Robert de Reymes fortified the house, when King Edward I granted him a licence to crenellate. Sited with three sides standing against the steep banks of the Cor Burn, it's one of the finest and most unaltered examples of its era. Early in the 14th century, an outer bailey curtain wall was added to guard the open side, with a plain arched gateway, a D-shaped and a rectangular flanking tower. The two storey hall block and kitchen wing with an embattled curtain wall make an inner courtyard, with the remnants of a middle courtyard to the west.