The castle was built to obtain control of a key route between London and the Midlands during the Norman conquest of England in the 11th century.

Robert of Mortain, William the Conqueror's half brother, was probably responsible for managing its construction, after which he became the castle's owner.

The castle was also used to hold royal prisoners, including King John II of France and rival claimants to the English throne.

After William the Conqueror defeated the Anglo-Saxons at the Battle of Hastings he advanced from the coast, across the Thames Valley and north into Hertfordshire.

[1] The actual construction work was probably overseen by William's half-brother, Robert of Mortain, who owned it by the time of the writing of the Domesday Book.

[3][4] The castle was located slightly away from the main road, to give additional space for the earthworks involved, and was positioned as to benefit from natural springs running down from under the hill.

In early 1215, King John installed a trusted German mercenary called Ranulph in charge of Berkhamsted Castle and reviewed the defensive arrangements there that April.

[25] The prince deployed his siege engines, probably trebuchets, and attacked the castle repeatedly for twenty days, throwing what chroniclers termed innumerable "damnable stones" at the defenders.

[29] When the forces loyal to the young Henry III defeated the rebels the following year, the castle was returned to royal hands.

[30][31] Henry III's brother, Richard, became the Earl of Cornwall and inherited the castle from his mother Isabella, and it became a permanent part of the earldom.

[33] Richard had an impressive, three-storey tower built onto the property in 1254, and restored much of the rest of the castle; the chroniclers of nearby Dunstable complained that his building works required so many carts to carry the timber that local trade in other goods was badly affected.

[6] When John died, Edward III reclaimed Berkhamsted Castle; a survey showed it to be in need of substantial repairs.

[6] Edward had not yet improved Windsor Castle, so used Berkhamsted as his main property, investing considerable sums in renovating it.

[19] His son, Edward, the Black Prince, was created Duke of Cornwall and also made extensive use of the castle, which formed part of the new duchy.

[41] Henry IV lived in the castle after he deposed Richard in 1400, and he used the property to detain rival applicants to the throne.

[42] During this period Geoffrey Chaucer, later famous for his Canterbury Tales, oversaw renovation work on the castle in his role as a clerk.

[45] In 1580, the estate, including the ruins and the park, was leased by Elizabeth I to Sir Edward Carey, for the nominal rent of one red rose each year.

[49] The English Civil War of the 1640s largely passed Berkhamsted by, with the castle apparently playing no part in the conflict.

[50] In 1761 the wider estate and the castle were separated, the former being leased to the Duke of Bridgewater, while the latter remained in the direct control of the Duchy of Cornwall.

[54] The castle was ultimately specifically protected in the 1833 act that sanctioned the railway, forcing the track to take a route across the valley floor.

It was set up as a charity by Charlotte Catherine Anne, Countess of Bridgewater to feed destitute agricultural workers during the winter months.

[63] Following the outbreak of World War II, Berkhamsted Castle was used as a secret location to house a collection of public statues that had been removed from central London to protect them from bomb damage during the Blitz.

[65] A planned event to mark the 950th anniversary in 2016 was cancelled when English Heritage refused permission due to concerns about damage to castle fabric and health and safety.

In 1155, Thomas à Becket took over the castle as Lord Chancellor and converted the wooden fort into a stone fortress.

King Henry III granted the castle to Richard Earl of Cornwall in 1227, who then used it as his primary residence and administrative centre.

The original castle was rebuilt in stone and extended over many years, yet the position remains consistent with the initial build.