Bolingbroke Castle near Spilsby in Lincolnshire is a 13th-century fortress built around 1220 by Ranulf, Earl of Chester, constructed primarily from Spilsby greenstone. The castle is historically significant as the birthplace in 1367 of Henry of Bolingbroke, who became King Henry IV. The site features a well-preserved gatehouse, round towers and moat typical of medieval military design. During the English Civil War, the castle was besieged by Parliamentarian forces in 1643 and subsequently demolished in 1652 by parliamentary order. Today, managed jointly by Heritage Lincolnshire and English Heritage, the ruins remain a prominent example of 13th-century castle architecture and royal heritage.
