Ancient Monuments

History on the Ground

This site is entirely user-supported. See how you can help.

Cardiff Castle and Roman Fort

A Scheduled Monument in Castle (Castell), Cardiff (Caerdydd)

More Photos »
Approximate Location Map
Large Map »

If Google Street View is available, the image is from the best available vantage point looking, if possible, towards the location of the monument. Where it is not available, the satellite view is shown instead.


Latitude: 51.4824 / 51°28'56"N

Longitude: -3.1811 / 3°10'51"W

OS Eastings: 318080

OS Northings: 176596

OS Grid: ST180765

Mapcode National: GBR KHL.PK

Mapcode Global: VH6FD.T04F

Entry Name: Cardiff Castle and Roman Fort

Scheduled Date:

Source: Cadw

Source ID: 3388

Cadw Legacy ID: GM171

Schedule Class: Defence

Category: Fort

Period: Roman

County: Cardiff (Caerdydd)

Community: Castle (Castell)

Built-Up Area: Cardiff

Traditional County: Glamorgan


The monument consists of the remains of Cardiff Castle which form a significant collection of archaeological remains which include a Roman fort, a Norman motte and bailey, a medieval castle, 18th century buildings and the late 19th century additions and restorations of the 3rd and 4th Marquesses of Bute.

Roman Fort

The Roman fort is the earliest structure and parts of this still survive. There was a succession of four overlapping forts at Cardiff, whose original Roman name has been lost, and their occupation appears to have been more or less continuous throughout the Roman period. Cardiff's strategic position on the main east-west route along the coastal plain of south Wales, and its accessibility from the sea led to the establishment of a fort here very early on in the Roman conquest of Wales. The first fort was of earth and timber and dates from about AD 55-60. It was a large fort, covering a much larger area than that within the present walls, with the present enclosure towards its south-western corner. Part of an axial north-south road, the remains of a large timber building and part of another even larger building to its north-east have been excavated from this phase.

The first fort appears to have been short-lived, and was replaced by a second, also of earth and timber, which dates from the last quarter of the 1st century. This was much smaller than the first fort, and was positioned in the middle of its north side, with its southern half overlapping the northern end of the present enclosure. The few parts of it that have been excavated suggest a simple fort, with civilian 'strip houses' to the south. It too was short-lived and was replaced, in the early 2nd century, by a third fort more or less on the same lines, which was given a slightly more elaborate south gateway. To its south iron-smelting was carried out where there had previously been houses. In about AD 276-285 the last fort on the site was built to the south of, and overlapping the third fort. It remained in use for about a hundred years. The present day enclosure follows the lines of this last fort: its north, east and part of its south walls were built on top of the original Roman ones in the late 19th century by the 3rd and 4th Marquesses of Bute, and the west wall stands on Roman foundations. The Roman parts of the walls are demarcated by a band of reddish-coloured stone on the outside, and can be seen on the south, north and east sides. On the inside a long stretch of the Roman wall is visible in a covered gallery on the south side. It is 3m thick at the base, and where best preserved is 5.2m high. During construction there was a change of layout. At first the corners were rounded, but were changed to square, and towers were added along the walls. The towers were solid and five-sided and were placed at regular intervals along the walls. The gateways were in the middle of the north and south sides. Of the south gateway nothing remains, but its position is known. The footings of the north gateway were found and showed that it was a single narrow entrance flanked by two towers. The present north gateway is a reconstruction by the 3rd Marquess of Bute. Little is known about the interior of the last fort, and no stone buildings have been found.

Norman Motte and Bailey

The Norman motte, surmounted by a shell-keep, was built within the walls of the fourth Roman fort. On entering the castle the motte lies directly ahead in the north-west quarter of the Roman enclosure. It is a large circular mound, surrounded by a deep water-filled ditch, on top of which is a stone keep. The first castle was built in 1081 at the instigation of William the Conqueror himself. Like its Roman predecessor it secured the lowest crossing of the river Taff and benefitted from good land and sea communications. Cardiff Castle became the administrative centre of the Norman lordship of Glamorgan. This first castle consisted of a large ditched motte with a timber keep on it, and a walled ward to the north-west, which reused Roman walling on the west and south sides. A large earth bank was thrown up over the remainder of teh Roman wall to the east to form the outer bailey. The shell keep was the work of Robert, earl of Gloucester, (illegitimate son of Henry I). He held the lordship of Glamorgan from about 1113 to 1147. The keep consists of a simple circular shell with faceted walls which stand to their full height with a wall-walk around the top. Buildings that stood against the inside have disappeared and only a large fireplace and corbels remain to show where they were. The gate tower, stairs and lower gate are all 13th-14th century additions by the de Clares and Despensers.

Medieval Castle

Cardiff Castle continued as the headquarters of the lordship of Glamorgan throughout the Middle Ages, and as such remained one of the leading castles in south Wales. It was added to and strengthened, in particular by Gilbert de Clare in the second half of the 13th century, who built the Black Tower by the south entrance and a massive parapeted wall between it and the keep (now demolished and marked by modern low walling). The outer bailey was used for the shire hall (a large rectangular 15th century building) and houses of knights of the shire who were guarding the castle. Foundations of these buildings have been found during excavations. Further additions and alterations took place in the 15th century, when the castle was turned into a luxurious residence for the Beauchamp family by the building of new residential quarters and the Octagon Tower (its spire was added in the late 19th century) on the west side of the enclosure.

18th-19th century

Except for some 15th century work, the medieval parts of the west block of the castle have been largely altered or obscured on its east side and in the interior by later rebuilding, and in particulary by the works of the 3rd Marquess of Bute's architect William Burges.

The monument is of national importance for its potential to enhance our knowledge of Roman military organisation. The monument forms an important element within the wider context of the Roman occupation of Wales and the structures may contain well preserved archaeological evidence concerning chronology, layout and building techniques. The monument is of further national importance for its potential to enhance our knowledge of medieval defensive practices. The monument is well-preserved and an important relic of the medieval landscape. It retains significant archaeological potential, with a strong probability of the presence of both structural evidence and intact associated deposits.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.

Source: Cadw

Other nearby scheduled monuments is an independent online resource and is not associated with any government department. All government data published here is used under licence. Please do not contact for any queries related to any individual ancient or schedued monument, planning permission related to scheduled monuments or the scheduling process itself. is a Good Stuff website.