Bolingbroke Castle is an interesting 13th century stone enclosure fortress, founded by Randulf de Blundeville, earl of Chester. Surrounded by a large moat, are the remains of a hexagonal curtain wall, with a twin-towered gatehouse, an octagonal tower and semi-circular towers, flanking the angles. In the large rout yard, is a post-medieval earthwork fort, in the form of an embanked and ditched platform. The castle which was the birthplace of King Henry IV in 1367, was slighted after the Civil War. 11 miles south-west is Tattershall Castle and 14 miles north-east is Castle Hill, Withern.