Hertford was one of the burgs founded by King Edward the Elder during the English re-conquest of the Danelaw. It was no doubt soon after 1066 that William the Conqueror raised the castle beside the River Lea. In general form, Hertford Castle resembles Berkhamsted – a motte and bailey once surrounded by a double moat, with much of its flint curtain still standing. The earthworks of the castle do not compare favorable, since the motte is surprisingly small and the moats have long been filled in. Royal expenditure is recorded in 1171-74, and the curtain probably dates at least partially from that time. The octagonal tower at the south angle of the enclosure is a later medieval addition.
Like Berkhamsted, the castle endured its only recorded siege in 1216, falling to the rebels during the Dauphin Louis’ campaign to win the English throne. A frequent royal residence up to Henry III’s reign, the castle declined in favor thereafter. Edward III granted it to his mother, the indomitable Queen Isabella, and those trophies of Edward’s military successes-David II of Scotland and John II of France-both saw spells of imprisonment here. An equally reluctant royal visitor was England’s own Richard II, who was deposed in the castle before moving on to his death at Pontefract.
The castle enjoyed a revival under Henry IV. He built the brick gatehouse in 1461-65. The gatehouse is an oblong structure with shallow angle turrets, the plain surface of the walls being enriched just below parapet level by blank arcades echoing machicolations. This feature is enough to show that the gatehouse was more for show than for defense. However, the original arrangements have been obscured by later adaptation. Occupation of the gatehouse continued long after the rest of the castle had been abandoned, and in1790 it was enlarged.