Oxford Castle: A Norman Fortress and Historic Prison in Oxford
Site at a Glance
- Rating
- 4.4
- Popularity
- Medium
- Country
- United Kingdom
- Primary era
- Medieval
- External website
- Open
- Eras represented
- Medieval, Early Modern, Modern
- Civilizations
- Anglo-Saxon, British, English, Norman
- Site type
- Military
- Remains
- Castle
On this page14 sections
History
Oxford Castle is a partly ruined medieval castle in Oxford, United Kingdom, built by the Norman baron Robert D’Oyly the elder between 1071 and 1073. Probably ordered by William I after Oxford suffered extensive damage during the Norman Conquest, it became an urban stronghold and the centre of D’Oyly’s power in Oxfordshire. The castle later played a major part in the civil war known as the Anarchy, served as a county administrative centre and prison, and developed into the Oxford Castle and Prison heritage complex.
Norman foundation and the Anarchy
Archaeological evidence indicates Anglo-Saxon habitation on the site before the castle was built. The Norman fortress was established over part of Oxford’s Saxon town wall, although the fate of any earlier buildings in the area remains uncertain. Its first form was probably a large motte-and-bailey, consisting of a raised earth mound and an enclosed defensive area. The bailey may have been constructed before the motte, making the earliest arrangement a ringwork, or circular fortified enclosure. The castle may have followed the pattern of D’Oyly’s stronghold at Wallingford.
D’Oyly became Oxfordshire’s leading landowner and held the hereditary royal constableship of Oxford Castle. His Oxford possessions, including meadowland and a mill probably corresponding to Castle Mill, were recorded in the Domesday Book of 1086. The castle itself developed as part of the town’s western defences, using a branch of the River Thames as natural protection and diverting it to create a moat.
Robert D’Oyly the younger inherited the castle by the time of the Anarchy, the 12th-century civil war between supporters of King Stephen and Empress Matilda over the English succession. D’Oyly first supported Stephen but later joined Matilda, who used Oxford Castle as the base for her campaign in 1141. Stephen captured Oxford in 1142 and besieged Matilda inside the castle for about three months. His forces operated from siege mounds later known as Jew’s Mount and Mount Pelham.
Matilda escaped in December, although the circumstances remain uncertain. A popular tradition says that she crossed the frozen Castle Mill Stream dressed in white, while the chronicler William of Malmesbury wrote that she left through one of the gates. She reached Abingdon safely, and the castle surrendered to Stephen the next day. Robert D’Oyly died during the final weeks of the siege. Stephen granted the castle to William de Chesney for the remainder of the conflict, while its constableship later passed to Roger de Bussy before Henry D’Oyly reclaimed it in 1154.
Stone rebuilding and royal administration
Between the late 12th and early 13th centuries, the castle’s wooden palisades and keep were replaced with stone defences. During the Barons’ War of 1215–1217, an armed conflict involving rebellious barons and the forces of King John and Henry III, the castle was attacked and its defences were strengthened. In 1220 Falkes de Breauté demolished St Budoc’s Church to the south-east and built a fortified barbican to protect the main entrance. The remaining wooden buildings were also progressively rebuilt in stone, including the Round Tower in 1235.
Henry III converted part of the castle into a prison, particularly for troublesome university clerks, and improved the chapel in 1243 and 1246. Oxford Castle did not become a royal residence, because Beaumont Palace already stood to the north of Oxford. By 1327 its gates and barbican were in poor condition, with repairs estimated at £800. From the 1350s its military role declined, while its administrative and penal functions expanded. The castle became the centre of Oxfordshire county administration, a prison, and a venue for the county’s criminal court.
Assizes, or formal sessions of a county court, were held at the castle until the plague outbreak of 1577 known as the Black Assize. The outbreak killed the Lord Lieutenant of Oxfordshire, two knights, 80 gentlemen, the entire grand jury, and Sir Robert D’Oyley, a relative of the founder. Assizes were subsequently discontinued at the castle. By 1578 the barbican had been demolished to make room for housing.
Private ownership and Civil War destruction
James I sold Oxford Castle to Francis James and Robert Younglove in 1611. They sold it to Christ Church, a college of the University of Oxford, in 1613. The college leased the property to local families, during which period the castle deteriorated. A record from 1615 shows the keep still standing on its mound, together with St George’s Tower, parts of the curtain wall, additional towers, Castle Mill, and an entrance to the castle complex. Houses and gardens occupied more than half of the castle ditch, although water still remained in parts of it.
During the First English Civil War, Oxford became the Royalist capital. Parliamentary forces captured the city in 1646 under Colonel Richard Ingoldsby. They strengthened the castle, then removed most of its medieval stonework in 1649 and replaced it with earth bulwarks and gun platforms. When Charles II’s forces threatened the area, the Parliamentary garrison demolished these defences in 1652 and withdrew to New College. The keep was dismantled in the early 18th century, and the top of the motte was later shaped into its present landscaped form.
Prison, county buildings, and modern conservation
After the Civil War, Oxford Castle functioned mainly as the city’s local prison. Christ Church leased it to wardens who charged prisoners for board and lodging, and the prison possessed a gallows. Mary Blandy was executed there in 1752. Conditions deteriorated during the 18th century. The prison reformer John Howard inspected it several times in the 1770s and criticised its cramped size, poor state, and vermin.
Oxford County Justices bought the castle in 1785 and began rebuilding the prison under the architect William Blackburn. Daniel Harris completed the work in 1805 and became governor. With assistance from Edward King, Harris used convict labour for early archaeological excavations at the castle. New Road was driven through the bailey in the late 18th century, while the remaining moat was filled to allow construction of a new terminus for the Oxford Canal.
The site continued to change during the 19th century. County Hall was built in 1840–1841, followed by the Oxfordshire Militia Armoury in 1854. The prison was enlarged in 1876 and renamed HM Prison Oxford in 1888 as part of national prison reforms. It closed in 1996, after which the site returned to Oxfordshire County Council. The former prison was redeveloped as a mixed-use heritage and restaurant complex, and the heritage project opened on 5 May 2006. The project received the RICS Project of the Year Award in 2007.
Oxford Castle is protected as a Scheduled Monument, and its principal medieval and later elements have been Grade I listed since 1954. The surviving castle remains and former prison buildings now make up the Oxford Castle and Prison heritage attraction.
Remains
Oxford Castle occupied the western side of the medieval town in a defensive arrangement of motte, bailey, shell keep, curtain wall, towers, and moat. The motte and bailey were formed from layers of gravel strengthened and faced with clay. Castle Mill Stream, a branch of the River Thames, was diverted to provide the moat and additional protection. Later roads and buildings have altered the original ground plan, but the motte, sections of the medieval defences, and several prison structures remain within the modern complex.
Earthworks and medieval defences
St George’s Tower
St George’s Tower is built of coral rag stone and forms part of the stone curtain wall, the main enclosing defensive wall of the castle. It is rectangular, measuring about 30 by 30 feet, or 9 by 9 metres, at its base, and narrows markedly as it rises. Once regarded as a Norman tower, it is now generally considered a late Saxon structure dating from around 1020. Its different orientation from the later castle suggests an earlier phase, when it probably served as a watchtower beside Oxford’s original Saxon west gate. Its original height would have given a wide view over the city.
Motte and bailey
The original motte was approximately 60 feet, or 18 metres, high and 40 feet, or 12 metres, wide. Together with the bailey, it created the raised and enclosed layout characteristic of a motte-and-bailey castle. The later landscape of the mound reflects the removal of the keep and the reshaping that followed the castle’s military decline. New Road crosses the line of the north-eastern curtain wall and its two square towers, while parts of New Road, Castle Street, and Paradise Street follow the approximate line of the former outer moat.
Shell keep and underground chamber
The ten-sided stone shell keep was built in the 13th century to replace an earlier wooden structure. A shell keep was a stone-walled enclosure built around the top of a motte rather than a solid stone tower. The keep measured about 58 feet, or 18 metres, across and enclosed buildings around an inner courtyard only about 22 feet, or 7 metres, wide. Stairs descended about 20 feet, or 6 metres, to an underground stone chamber roughly 12 feet, or 3.7 metres, across. The chamber has an Early English hexagonal vault and a well about 54 feet, or 16 metres, deep, which could provide water during a siege.
Round Tower and barbican
The southernmost round tower survives at its base and is dated by documentary evidence to 1235. It is sometimes called Henry III’s Tower. The Round Tower was part of the wider stone rebuilding undertaken in the 13th century, when the remaining wooden buildings were replaced. The entrance was strengthened in 1220 by a barbican, a fortified outwork defending a gateway, positioned south-east of the castle and surrounded by a moat. Houses later replaced the barbican, and its remains lie beneath the modern Westgate shopping centre.
Chapel and prison buildings
St George’s Chapel and crypt
A chapel was attached to St George’s Tower and included a crypt. It may have replaced an earlier church and originally consisted of a nave, chancel, and apsidal sanctuary, the curved eastern end of a church. Its early Norman design used solid pillars and arches, and it was dedicated to St George at an early stage. The chapel was demolished in 1794 during construction of the new prison. Its crypt was then moved and reconstructed elsewhere within the castle using its original materials, so the surviving structure stands in a different position from the medieval chapel.
Former prison complex
The later complex incorporates the D-Wing, the Debtors’ Tower, County Hall, the former militia armoury, a former laundry, the Governor’s Office, the Governor’s House, the Front Range, the C Wing and Round Tower, the boundary wall, and the former Houses of Correction with an attached carpenters’ shop. These buildings express the castle’s long transformation from fortified stronghold to county institution and prison.
The former prison blocks now contain a hotel, with former cells converted into guest rooms. Areas associated with corporal and capital punishment were converted into offices rather than accommodation. The later buildings stand alongside the medieval tower, earthworks, well chamber, relocated crypt, and fragments of the original castle, preserving the successive military, administrative, and penal uses of the site.
