Although the settlement of Warkworth in Northumberland dates back to at least the 8th century, the first castle was not built until after the Norman Conquest. The town and its castle occupied a loop of the River Coquet. The castle was built at the south end of the town, guarding the narrow neck of the loop. A fortified bridge also defended the approach to the town. The surrounding lowland countryside was favourable for agriculture. When the castle was founded and by whom is uncertain, though traditionally Prince Henry of Scotland, Earl of Northumberland, has been thought responsible. With civil war in south-west England, King Stephen of England needed to ensure northern England was secure. To this end, the Treaty of Durham in 1139 between Scotland and England ensured peace. Under the treaty Henry of Scotland became Earl of Northumbria in exchange for ceding control of the castles at Bamburgh and Newcastle to the English. Without them Henry would have needed a new seat from which to exercise his authority, and a new castle at Warkworth may have met the requirement. However, charters show that Henry still controlled Bamburgh Castle after the treaty, and as Warkworth was a modest castle by contemporary standards it may be have been founded by someone else. Henry died in 1152 and his son, Malcolm (crowned King of Scotland in 1153), inherited his lands. In 1157 Malcolm travelled to Peveril Castle in Derbyshire, where he paid homage to the new King of England, Henry II. Malcolm surrendered England's northern counties to Henry, including the castles of Bamburgh, Carlisle, and Newcastle, and probably Appleby, Brough, Wark, and Warkworth, though it is possible that Henry II founded Warkworth Castle in 1157 to secure his lands in Northumberland; other contemporary castles in the area were built for this purpose, for instance the one at Harbottle.
The first mention of Warkworth Castle occurs in a charter of 1157–1164 from Henry II granting the castle and surrounding manor to Roger fitz Richard, a member of a noble Norman family. It has been suggested that this charter may have used the term castle to describe a high-status residence on the site, possibly dating from the Anglo-Saxon period, meaning Roger may have built the castle. He owned lands across a wide area, and Warkworth may have been of little significance in the context of his other holdings. When the Scots invaded Northumberland in 1173, although Roger fitz Richard was in the county Warkworth Castle was not defended by its garrison. Its defences at the time were described as "feeble". In 1174 Duncan II, Earl of Fife, raided Warkworth. The contemporary record does not mention the castle, and instead notes that Warkworth's inhabitants sought refuge in the church. When Roger fitz Richard died in 1178 his son and heir, Robert fitz Roger, was still a child. A guardian looked after the family estates until Robert came of age in 1191. He paid the Crown 300 marks in 1199 for confirmation of his ownership of Warkworth, including the castle. Substantial building work at Warkworth Castle is attributed to Robert. A favourite of King John, Robert hosted him at Warkworth Castle in 1213.
Warkworth Castle continued to descend through the family line when Robert fitz Roger was succeeded by his son John in 1214, who was succeeded by his son Roger in 1240. Roger died in 1249 when his son Robert was one year old, and a guardian was appointed to care for the family's estates: William de Valence, half-brother of King Henry III. The castle, characterised by this time by the chronicler Matthew Paris as "noble", remained under the guardianship of Valence until 1268, when it reverted to Robert fitz John. King Edward I of England stayed at Warkworth Castle for a night in 1292. The English king was asked to mediate in a dispute over the Scottish throne and laid his own claim, leading to the Anglo-Scottish Wars. After the Scottish victory at the Battle of Stirling Bridge in 1297, Robert and his son, John de Clavering, were captured. They were subsequently released and in 1310 John assumed control of the family estates. A year later, John made arrangements so that on his death the king would receive all of his property. Between roughly 1310 and 1330 the English struggled to deal with Scottish raids in northern England. Such was the importance of large castles during the Scottish Wars that the Crown subsidised their maintenance and even construction. In 1319, King Edward II paid for a garrison for the castle of four men-at-arms and eight hobilars to enhance the existing force of twelve men-at-arms. Ralph Neville was the keeper of Warkworth Castle in 1322. As he was married to John's daughter, Euphemia, Ralph may have hoped to inherit the Clavering estates, but that did not happen. Twice in 1327 Scottish forces besieged the castle without success.
Around this time, the Percy family was becoming Northumberland's most powerful dynasty. Henry de Percy, 2nd Baron Percy, was in the service of Edward III and was paid 500 marks a year in perpetuity in return for leading a company of men-at-arms. In exchange for the annual fee, in 1328 Percy was promised the rights to the Clavering estates. Parliament declared such contracts illegal in 1331, but after initially relinquishing his claim Percy was granted special permission to inherit. John de Clavering died in 1332 and his widow in 1345, at which point the family's estates became the property of the Percys. While the Percys owned Alnwick Castle, which was considered more prestigious, Warkworth was the family's preferred home. Under the Percys a park was created nearby for hunting, and within the castle two residential blocks were created, described by historian John Goodall as "of unparalleled quality and sophistication in Northumberland". The second baron died at Warkworth in 1352.
In 1377 the fourth Baron Percy, also named Henry, was made the first Earl of Northumberland (becoming the first family from northern England to be granted an earldom) in recognition of his extensive power in the march areas along the Anglo-Scottish border. With a network of contacts and dependencies, the Percys were the pre-eminent family in northern England in the 14th century "for they have the hertes of the people by north and ever had", in the words of contemporaneous chronicler John Hardyng. Henry Percy commissioned the building of the distinctive keep shortly after he was made Earl of Northumberland. Percy may have enhanced his main castle to compete with John of Gaunt, who rebuilt the nearby Dunstanburgh Castle, or with the House of Neville, a family becoming increasingly powerful in northern England and who undertook a programme of building at the castles of Brancepeth, Raby, Bamburgh, Middleham, and Sheriff Hutton. Architectural similarities between Warkworth's keep, Bolton Castle, and the domestic buildings at Bamburgh Castle suggest that John Lewyn was the master mason responsible for building Warkworth's keep. Earl Henry helped dethrone Richard II and replace him with Henry IV. The earl and his eldest son Henry "Hotspur" Percy fell out with the new king, and eventually rebelled. After Hotspur was killed at the Battle of Shrewsbury in 1403, his father fled to Warkworth. The earl eventually went to York to submit to the king. He was arrested and the king attempted to install his own men at the castles of Alnwick, Langley Castle, Prudhoe, and Warkworth. The earl's 14-year-old son claimed that he was loyal to the king but was not empowered to formally surrender the castle, and it remained under control of the Percys. Henry was pardoned in 1404.
Earl Henry rebelled again in 1405, this time joining the unsuccessful revolt of Archbishop Scrope. While Henry was fleeing north after the failed rebellion, his castles offered some resistance before submitting to royal forces. Warkworth itself was well-provisioned and the garrison initially refused to surrender. However, according to a letter written by Henry IV from Warkworth after its fall, after just seven shots from his cannon the defenders capitulated. The castle was forfeited to the Crown, and was used by one of the King's sons, John, Duke of Bedford, who was appointed to rule the area. It remained in the ownership of the Crown until Henry V restored it to the Percy family in 1416, and at the same time made the son of "Hotspur" Henry, another Henry Percy, second Earl of Northumberland. It is known that the second earl resided at Warkworth and undertook building work there, but it is now unclear for which parts he was responsible.
The Percys supported the House of Lancaster during the Wars of the Roses, and the second earl and his successor – Henry Percy, 3rd Earl of Northumberland – were killed at the battles of St Albans in 1455 and Towton in 1461 respectively. The new king, Edward IV, issued an attainder against the family and their property was confiscated. On 1 August 1464, as a result of suppressing Lancastrian rebellions in the north for the previous three years, the title of Earl of Northumberland was given to The 1st Marquess of Montagu, a Yorkist, and with it, the castle. During his tenure, he constructed a twenty-five-foot tall rectangular tower, built for defence, "with [arrow] slits in the three outer walls;" this is known as 'Montagu's Tower' to this day. His brother, The 16th Earl of Warwick, used Warkworth as a base from which the Lancastrian-held castles of Northumberland – Alnwick, Bamburgh, and Dunstanburgh – were attacked and their sieges co-ordinated. In 1470 Edward IV returned the Percys' estates to the eldest son of the third earl, who was also called Henry Percy. A year later Henry was granted the earldom of Northumberland. Some time after 1472 Henry remodelled the building of the bailey. He also planned to build a collegiate church within the castle, but the work was abandoned after his death. When the fourth earl was murdered in 1489, his son, Henry Algernon, inherited and maintained the castle. In the early 16th century Henry Percy, 6th Earl of Northumberland, was responsible for clearing the collegiate church founded by his grandfather, but left incomplete by the fifth earl. Thomas Percy, brother of the sixth earl, was executed for his role in the Pilgrimage of Grace in 1536. When Henry Percy died the next year without any sons, the family's property passed to the Crown. Although royal officers still used the castle, by 1550 it had fallen into disrepair. In 1557 the Percy estates were restored to the descendants of Thomas, and the nephew of the sixth earl, another Thomas Percy, was given the earldom. He began a programme of repairs at the castle, and in the process dismantled "the hall and other houses of office".
The Rising of the North in 1569 saw Catholic nobles in northern England rebel against the Protestant Queen Elizabeth I. The Catholic Thomas Percy joined the rebellion and supporters congregated at the castles of Alnwick and Warkworth. Sir John Forster, Warden of the March, ordered those inside to leave and the castles were surrendered to his control. During the conflict that followed, Warkworth remained under royal control. Forster pillaged the castle, stripping it of its timbers and furnishings. The keep at least did not share in this fate, but in April 1572 Henry Carey, 1st Baron Hunsdon, bemoaned the treatment meted out to the Percy castles, writing to the queen's chief minister, "It is a great pity to see how Alnwick Castle and Warkworth are spoiled by him ... I am creditably informed that he means utterly to deface them both." An attainder was issued against Thomas Percy so that when he came into English custody he was executed without trial on 22 August. As a result, Percy's son was passed over, but under the terms of the attainder his brother was allowed to inherit. In 1574, Elizabeth granted Henry Percy permission to inherit the family's property and assume the title of 8th Earl of Northumberland.
The castle formed the backdrop for several scenes in William Shakespeare's Henry IV, Part 1 and Part 2. Another Henry Percy inherited the family estates in 1585 and assumed the title of 9th Earl of Northumberland. After the failed Gunpowder Plot of 1605, the earl was imprisoned for his connection with Thomas Percy, one of the plotters. Shortly before he was sentenced (he was fined £30,000 and held in the Tower of London), the earl leased Warkworth Castle to Sir Ralph Gray, who owned Chillingham Castle in Northumberland. Gray neglected the earl's building and allowed it to fall further into disrepair. The lead from the buildings in the bailey was sold in 1607 to alleviate the earl's financial problems. When James I visited in 1617 en route to Scotland, his entourage was angered by the sorry state of the castle. With the unification of England and Scotland under a single ruler, the earls of Northumberland had no need for two great castles near the Anglo-Scottish border; they maintained Alnwick at the expense of Warkworth. In the first quarter of the 17th century, the keep was used to hold manor courts and for the laying out of oats.
The details surrounding Warkworth Castle's role in the English Civil War are unclear, but the conflict resulted in further damage to the structure. Initially held by Royalist forces, the castle was still important enough that when the Scots invaded in 1644 they forced its surrender. Algernon Percy, 10th Earl of Northumberland, supported Parliament, which may have prevented the Scots from doing much damage to the castle. Parliamentarian forces took over the castle in 1648; when they withdrew they removed the castle's doors and iron so that it could not be reused by the enemy. They may also have partially demolished some of the castle, and may be responsible for its present state. Algernon Percy unsuccessfully applied for compensation in 1649 for the damage.
Dukes of Northumberland and present day
The 11th Earl of Northumberland, the last Percy earl, died in 1670. Two years later his widow allowed the keep's materials to be reused to build Chirton Hall. A total of 272 cart-loads were taken from the keep. Lord Northumberland's property passed to The 7th Duke of Somerset through marriage. In 1698, the owners decided not to renovate Warkworth Castle after the estimate to add battlements, floors and new windows came in at £1,600. Lady Elizabeth Seymour inherited the property from her father in 1750. Her husband, Hugh Smithson, changed his name to Hugh Percy, and the castle then descended through the Dukes of Northumberland, a dynasty he founded.
During the 18th century the castle was allowed to languish. The south-west tower was falling apart and around 1752 part of the curtain wall east of the gatehouse was demolished (it was rebuilt towards the end of the century). The town and its historic ruins were by now attracting interest as a tourist destination, largely due to Bishop Thomas Percy's poem, The Hermit of Warkworth. In the mid 19th century, The 3rd Duke of Northumberland undertook some preservation work. His successor, The 4th Duke of Northumberland, contracted Anthony Salvin to restore the keep. The work undertaken between 1853 and 1858 was not as extensive as Salvin had planned, and was limited to partially refacing the exterior and adding new floors and roofs to two chambers, which became known as the Duke's Chambers, on the second floor. The Duke occasionally used the chambers for picnics when he visited from Alnwick Castle. The 4th Duke funded excavations at the castle in the 1850s which uncovered the remains of the collegiate church within the bailey.
In 1922, The 8th Duke of Northumberland granted custodianship of the castle to the Office of Works which had been made accountable for the guardianship of ancient monuments. The Duke's Chambers remained under the direct control of the Percys. The Office of Works undertook excavations in the moat in 1924 and removed the custodian from the gatehouse. English Heritage, who now manage and maintain the site, succeeded as the castle's custodians in 1984, and three years later the Duke's Chambers were given over to their care. The castle is a Scheduled Ancient Monument, a "nationally important" historic building and archaeological site which has been given protection against unauthorised change. It is also a Grade I listed building (first listed in 1985) and recognised as an internationally important structure. The castle continues to be officially owned by the Percy family, currently being owned by His Grace The 12th Duke of Northumberland.