Newark Castle, in Newark, Nottinghamshire, is thought to have been founded by Egbert, King of the West Saxons, was partly rebuilt and greatly extended by Alexander, consecrated Bishop of Lincoln in 1123, who established it as a mint.
All that remains of the original Norman stronghold are the gate-house, a crypt and the lofty rectangular tower at the south-west angle. The building seems to have been reconstructed in the early part of the 13th century. King John of England died at this castle on 19 October 1216. In the reign of Edward III it was used as a state prison.
During the English Civil War, Newark was a mainstay of the royalist cause, Charles I having raised his standard in nearby Nottingham. It was attacked in February 1643 by two troops of horsemen, but beat them back. The town fielded at times as many as 600 soldiers, and raided Nottingham, Grantham, Northampton, Gainsborough, and others with mixed success, but enough to cause it to rise to national notice.
At the end of 1644 it was besieged by forces from Nottingham, Lincoln and Derby, the siege was only relieved in March by Prince Rupert of the Rhine. Parliament commenced a new siege towards the end of January 1645 following more raiding, but this was relieved by Sir Marmaduke Langdale after about a month. Newark cavalry fought with the king's forces which were decisively defeated in the Battle of Naseby, near Leicester in June 1645. The final siege began in November 1645, by which time the town's defences had been greatly strengthened. Two major forts had been constructed just outside the town, one, called the Queen's Sconce, to the south-west and another, the King's Sconce to the north-east, both close to the river, together with defensive walls and a water filled ditch 2¼ miles in length, around the town. In May 1646 the town was ordered to surrender by Charles I, which was still only accepted under protest by the town's garrison. After the surrender most of the defences were destroyed, including the castle. the remains can still be seen today.