Medieval motte and bailey castle.
Saxon cemetery was discovered below the southern bailey rampart.
1067 Built by William Fitz Osbern under the orders of William I, as a motte and bailey castle.
1069 Royal castle.
1074 Ralph Fitz Osbern and his younger son, Roger, rose a revolt against the king but their bid failed and they were given 40 days to leave the country.
1075 Surrendered on the agreement that the garrison could all leave England.
1075 The defence of the castle was maintained by the wife of Earl Ralph.
1077 Roger Bigot held the castle in the position of Constable for the King.
1087-1088 Besieged by Roger Bigod during his revolt against William II.
1090 Stone keep was built.
1100 Motte heightened and the ditch was dug deeper.
1103 Henry I stayed at the castle.
1108 Henry I stayed at the castle.
1122 Henry I stayed at the castle.
1125-1135 The Great Tower was built measuring approximately 95ft by 90 ft and standing 70ft high. It contained a large hall and chamber on the first floor with garderobes, chapel and a room for the castallian. The ground floor contained storage chambers and the armoury. The second floor comprised of guard rooms and a gallery inside the walls all around. The tower had a kitchen and was built of ashlar blocks of Caen stone and faced with flint work core.
1136 Hugh Bigod laid seige to the castle.
1154-1189 During: Henry II took the castle from one of Stephen’s sons, the Count of Mortain. He then carried out some works including a double palisade.
1165/6 First used as a gaol.
1172-1173 Bridge repaired.
1173-1174 Hugh Bigod, Earl of Norfolk, captured the castle for Prince Henry during his revolt against his father Henry II.
1174 Henry II garrisoned the castle with 300 men-at-arms, archers and engineers.
1216 Captured by Louis of France, who held it for a year.
1220 Used as a gaol with additional buildings added.
1268-1270 The wooden defences were replaced by a stone curtain wall at the cost of £500.
1290 Edward I rebuilt the hall in the great tower and spent around £500 on it.
1345 Edward III gave the two baileys to the city.
1381 Geoffrey Lister took the castle over during the Peasants Revolt.
15th C Derelict, abandoned.
1642-1651 Civil War: Held by Parliament. Artillery battery built on the north east side of the mound.
1707-1709 £1,300 was spent on repairs.
1789-1795 Used as a prison. The prison was designed by John Soane to a U-shaped plan. The prison buildings added in 1220 were demolished.
1790 The walls were replaced.
1820 Alterations made to the gaol buildings.
1822-1828 New prison plans drawn up and built by William Wilkins.
1825 The Norman bridge was replaced.
1830 Lower part of the keep was redressed in stone.
1834-1839 Keep rebuilt to its original design by Anthony Salvin.
1839 Until: Used as a prison.
1856 New prison cells were approved.
1884 Bought by Norwich Corporation for £4000.
1887 Prison closed.
1888-1894 Made into a museum by Edward Boardman at a cost of £22,000.
1894 23rd October: Museum opened to the public.
19th C Rebuilding has hidden the original castle work. Alterations made to the prison.
1979 Excavated.. Scheduling amended.
1992 Watching Brief.
1993 Watching Brief.
1993-1994 Watching Brief.nit.
1995 Architectural Survey.
1999 Watching Brief.
2000 Watching Brief.
2001 Architectural Survey..
2005 Watching Brief.