[2] The Normans built a motte-and-bailey castle in the late 11th century; the motte is one of the largest of its kind in Great Britain.

William the Conqueror gave Pleshey, in the parish of High Easter (southwest of Braintree), to Geoffrey de Mandeville.

At Pleshey, Mandeville built his caput (centre of administration and main home) of the many villages in Essex given to him by the king.

Humphrey de Bohun VIII (4th Earl of Hereford and 3rd of Essex (1275?-1322) on 14 Nov. 1302 married Elizabeth, the daughter of Edward I, King of England.

In 1327, Pleshey Castle became the primary residence of Humphrey VIII's eldest surviving son, John de Bohun, created Earl of Hereford and Essex.

The castle then passed (through the marriage of Eleanor) to Thomas of Woodstock, Duke of Gloucester, the youngest son of Edward III.

The castle was dismantled in 1158 when Henry II returned the de Mandeville lands to Geoffrey III, but was subsequently rebuilt in 1167 by William II de Mandeville, which was completed following the same plan as before yet including a massively enlarged rampart enclosing the south bailey.

The completion of these buildings has been dated to the late 14th century and are attributed to the de Bohuns and Thomas of Woodstock, 1st Duke of Gloucester.

The keep's great hall has also been located, whilst other ranges are thought to represent 'en suite' accommodation, each with their own fireplace and privy.

This could be because it was replaced in function; evidence of facility duplication exists with late-medieval halls present in both the keep and the south bailey.

The final renovation of the keep was carried out on the orders of Margaret of Anjou, wife of Henry VI, in 1458–1459, where the keep is referred to as a "tower" and was mainly built from the timber of at least 29 oaks, finished in flint, and later brick, facades.