Bolingbroke Castle

Bolingbroke Castle is a ruined castle in Bolingbroke (now Old Bolingbroke) in Lincolnshire, England.

Construction

Most of the castle is built of Spilsby greenstone, as are several nearby churches. The local greenstone is a limestone that proved to be porous, prone to rapid deterioration when exposed to weather and a substandard building material. The castle was constructed as an irregular polygonal enclosure. The castle is one of the earliest examples of a uniform castle designed and built without a keep. It was originally surrounded by a large water-filled moat 31 metres (102 ft) wide. The curtain wall was up to 5 metres (16 ft) thick and defended by five D-shaped towers and a twin-towered gate house.

Similar to another castle built by Ranulf during the same period at Beeston in Cheshire, Bolingbroke had no inner defensive keep. The castle relied instead on thick walls and the five D-shaped defensive corner towers. Some design similarities are noted with the contemporary castle at Boulogne-sur-Mer, France that was also constructed without a central donjon.

History

The area was first fortified by the Saxons in the 6th or 7th century. In the 12th century the Normans built a Motte-and-bailey on a nearby hill above the settlement of Bolingbroke.¹ The present structure was founded by Ranulf, Earl of Chester, in 1220 shortly after he returned from the Fifth Crusade.²

Ranulf died in 1232 without a male heir, and his titles, lands and castles passed to his sisters. Following the death of Henry of Grosmont, 1st Duke of Lancaster in 1361, Bolingbroke passed through marriage into the ownership of . His wife , daughter of Henry of Grosmont, was born at the castle in 1342. John and Blanche's son, , was also born at Bolingbroke Castle in 1367 and consequently was known as "Henry Bolingbroke" before he became king in 1399.