Portchester Castle in Hampshire has a dramatic setting right on the coast, at the edge of a promontory on the north side of Portsmouth Harbour, benefiting from commanding views south across the water and north towards the white chalk cliffs of Ports Down. The oldest part of the castle dates from the early 12th century, but the buildings are enclosed by walls up to 800 years older, from the Roman fort of Portus Adurni. Apart from a short section replaced by the Castle, the walls are complete, and remarkably well preserved, retaining their original height of 20 feet, and most of the two main gates, together with 14 supporting towers.
The castle consists of a gatehouse, a palace (hall block), several lesser ranges, a tower and a great keep, and is accessed via a bridge over a moat, which contains shallow water. The site is relatively small, and the most impressive component is undoubtedly the keep, which unlike the rest of the buildings has been continuously maintained, used for military purposes as recently as the Napoleonic wars (1799-1815) to house prisoners. It contains several intermediate floors and over a dozen large rooms, and two flights of stone stairs lead all the way to an open area on the roof, a hundred feet up, a vantage point that has long distance views in all directions.
An entrance fee is charged for the castle, though not for the fort, the walls of which also enclose a parish church, Saint Mary's; this originally formed part of a small Augustinian priory established in 1128, the other buildings from which have long since disappeared. A visit to the castle and the church, and a walk all around the ancient Roman walls that run in part along the scenic shoreline, is definitely a historic highlight of Portsmouth. The fort is regarded as the best preserved of any in northern Europe.
The approach to the castle is along the appropriately named Castle Street through Portchester village, a few miles from exits 11 and 12 of the M27; the road ends in a small, free car park beside Portchester Sailing Club. Parkland extends to the north, along the edge of the harbour (this section is known as Paulsgrove Lake), while the fort and castle are to the south - the entrance is along a short path that crosses a water-filled channel, originally the Roman ditch, then leads through a gate in the north wall of the fort. The second main entrance is from the west, via a paved road (Church Lane), which continues across the fort to a third gate, usually closed, on the east side. Another, half mile path goes all around the exterior of the fort, which adjoins grassy areas to the north, west and part of the south, and muddy, tidal flats on the other side. The castle occupies approximately the northwestern quarter of the fort, while the church and its extensive graveyard are in the southeastern quadrant; the other half is empty, though once contained several lesser structures including a barn.
The entrance to the main part of the castle, centred on the inner bailey, is through the gatehouse, accessed via a wooden bridge over the moat. The earliest section of the gatehouse was built in the 12th century, after which the structure was extended on three occasions, most recently in the 17th century, resulting in a mix of different masonry styles. Several portcullis slits can be seen, and the entry passage extends for an unusually long 70 feet. The southwest corner of the bailey is the site of Richard II's palace, built during the last few years of the 14th century; on the lower level this had a kitchen, storerooms and pantry, with an elegant entrance porch, while above was a great hall. The roof and intermediate floor are long gone, but windows and fireplaces in the upper level give some hints as to the visual appearance of the hall. This building is linked to the keep by the west range, which contained private chambers for the royal family. In the northeast corner is a square tower, built around 1376 by constable Sir Robert Ashton, together with a smaller hall above a residential room, which extended part of the way along the north wall. Other, minor rooms occupied the east side and part of the south, but the interior of the castle is dominated by the great keep, to the northwest. The lower section of the keep was erected in the mid 12th century, though like the gatehouse the tower was extended several times, attaining its final height of just over 100 feet at the end of the 14th century. A full height, west-east dividing wall partitions the tower into two sections, separately accessed by spiral staircases. Some rooms in the castle contain exhibits about its history, but most are empty. One other feature of interest is the wall of one of the upper rooms on the south side, which is adorned with several wall paintings and many inscriptions, dating from the middle of the 19th century. At the base of the tower are several other rooms including a chapel, jail cell and exchequer's office.
The Romans built the fort of Portchester towards the end of the third century, by order of the emperor Diocletian, and held it for about the next 130 years, until all Roman legions left England, but it seems likely that the place was immediately re-occupied by the local English population. Later Saxon additions included new east and west gatehouses, with smaller, more easily defended doorways, and although subsequently further modified, some of the Saxon masonry also survives. The walls of the fort are perfectly square in outline, and were guarded by 20 evenly spaced, D-shaped towers, or bastions - one at each corner, and four along each edge; 14 remain. The walls were built mostly of flint pebbles, augmented by thin rows of white limestone and red bricks. The Saxons also added some structures within the walls, but the next earliest building still visible is the castle, which was begun at the end of the 11th century, though it was initially constructed with wood; the first stone structures - the keep, the walls and part of the gatehouse - are a little later, probably from the 1120s. The earliest occupiers were several local landowners, until the castle passed to the crown around 1154, and subsequently acted as a departure base for several military expeditions into France, by kings including John, Henry III and Henry V. The buildings were extended and remodelled on several occasions over the next 200 years, until royal use declined around the start of the 15th century. The place was later repaired and re-occupied in the middle of the 16th century, and frequent royal visits continued until 1632, when it was sold, by King Charles I. Amongst the later uses was as a prison, as recently as the early 19th century.