In 1998 English Heritage passed the management of the site back to its current owner, Baron Howard of Rising, who continues to operate the castle as a tourist attraction.

Castle Rising comprises three baileys, each defended by large earthworks, covering a total area of 5 hectares (12 acres), which archaeologists Oliver Creighton and Robert Higham consider to be among the most impressive in Britain.

Historians Beric Morley and David Gurney believe this to be "one of the finest of all Norman keeps", and its military utility and political symbolism have been extensively discussed by academics.

Castle Rising was built soon after 1138 by William d'Aubigny II, an upwardly mobile Anglo-Norman noble who owned the surrounding manor of Snettisham.

[1] This transformed his social position, and one chronicler at Waltham Holy Cross complained how he "became intolerably puffed up ... and looked down upon every other eminence in the world except the King".

[5][a] Following the Norman Conquest of England, the land had been granted to Bishop Odo, the Earl of Kent, who may have used it as an administrative centre; there were many Saxo-Norman buildings on the site of the later castle.

[14] William received permission from King Stephen to open a mint at the castle in 1145 and, probably linked to this development, settled a community of Jews in the town.

Henry clamped down on the operation of the regional mints, however, and closed the facility at Castle Rising; the local Jews resettled in King's Lynn.

[29] An alternative theory to explain the different style of stonework along the top of the keep is that the building was completed under William d'Albini II, but had become dilapidated by the start of the 14th century, requiring extensive repairs by Robert.

[30] The forebuilding of the keep was raised in height at one end around this time and a new, peaked roof added to it, and an imposing, timber-framed, brick kitchen was built in the inner bailey.

[31] At the time of Robert's agreement with the Crown, the government of England was controlled by Roger Mortimer and Queen Isabella of France, who was ruling as regent in the name of her young son, Edward III.

[32] Isabella fell from power when Edward toppled Mortimer in a coup d'état in 1330, but after a short period of house arrest she led a relatively normal life, enjoying considerable status as the King's mother.

[34] She enjoyed a regal lifestyle in Norfolk, maintaining minstrels, huntsmen and grooms, and received visits from Edward and the royal household on at least four occasions.

[40] Edward III had decreed in 1337 that his son would inherit the castle after Isabella's death, complete with the surrounding manor and the right to part of the tolls from King's Lynn, although these brought in only a relatively modest £100 a year.

[43][f] The Prince died in 1376, returning the Duchy of Cornwall to the control of the Crown, and during this time Castle Rising appears to have been maintained in good condition.

[53] Reports in 1482 stated that the buildings were no longer weatherproof, and a survey carried around between 1503 and 1506 described the castle as "evyll repayred", and noted that the roof of the keep was rotten.

[58] At around this time, the forebuilding of the keep was adapted to form a separate, smaller, set of chambers, and at some point after this a passageway was dug out of the walls to link these to the kitchens in the keep, by-passing the now floor-less rooms of the keep.

[65] The ground level of the inner bailey, which had built up over the years, was lowered by about 1 metre (3 ft 3 in): according to the contemporary archaeologist Henry Harrod, this process required thousands of loads of earth to be dug out and removed.

[66] A great deal of medieval archaeological evidence was destroyed in the process, but the work uncovered the old Norman chapel and Harrod excavated the building in 1851.

[79] A dovecot and a religious house were founded nearby; both of these were important symbols of lordship at the time, and were considered essential parts of a properly established castle.

[83] It utilised marginal farm-land, which may have contributed to its design; the heathland and light woodland south of the castle would have been ideal for grazing deer.

[86] The earthworks of Castle Rising cover a total area of 5 hectares (12 acres), and are considered by archaeologists Oliver Creighton and Robert Higham to be among the most impressive in Britain.

[92] Some of the remains of the 14th-century brick wall, built on an additional 1 metre (3 ft 3 in) layer of limed sand for stability, have survived along part of the bank.

[94] The main architectural focus of the inner bailey was the great keep, but it also contained a Norman chapel and, from at least the 14th century onwards, a complex of smaller residential and service buildings.

[106] The keep is built from courses of local, brown carrstone rubble with oolite ashlar facings, and is strengthened with intramural timbers, laid down within the stone walls to reinforce the structure.

[121] The upper 3.7 metres (12 ft) of the keep's walls are different in design to the main body of the building; as described above, this may be the result of either a final phase of construction between 1200 and 1230, or a period of repair and renovation shortly after 1300.

[122] Many 20th-century historians have stressed the potential military strength of Castle Rising; R. Allen Brown, for example, concluded that "defence ... was the overwhelming consideration in [its] design and construction", and argued that the keep would have been used as a final refuge in the case of attack during a siege.

[127] They reflected lordly status: typically their owners had recently advanced up the social scale, as with William d'Aubigny, and were keen to impress others with their new authority.

[129] As they came through the gatehouse and past the earthworks into the bailey, the south side of the forebuilding - deliberately facing the entrance - would have been revealed, covered in fashionable carving and decorative features.

[130] Visitors would then have walked up the stairs of the forebuilding, have paused in a waiting room, originally largely open to the elements, before being allowed through a decorative entrance door.