Slingsby Castle was originally a fortified manor house or hunting lodge, founded by the de Mowbrays. In 1344, Ralph de Hastings founded the stone castle, when he was granted a licence to crenellate his manor house. In 1474, another licence was issued to William, Lord Hastings to build, enclose and crenellate the castle or manor. The large rectangular platform, encased by a wide moat, now supports the ruins of an early 17th century Jacobean mansion. Probably built by John Smythson, for Sir Charles Cavendish, it was probably left unfinished, when he fled to the continent in 1644. Built of limestone with ashlar dressings, the two storey house was quadrangular in plan, with five bays and projecting stair turrets on the angles. 6 miles south-west is Malton Castle and 7 miles south is Sheriff Hutton Castle.