The modern entrance to the castle is from the east, following the medieval route through the bailey, within which lie low grassy footings of the later medieval service buildings. These were protected by a gatehouse, a wall and a massive rock-cut ditch. Excavations have shown that this ditch was in fact a recut of a much earlier one, dug as part of a defensive system cutting off the ridge in pre-Norman, perhaps Iron Age times.

Little now remains of the earth and timber castle that was built here by the Norman Gerald of Windsor around 1100. It is first mentioned in 1212, when for some reason, King John seized it for a short time when passing through Pembroke on his Irish expedition. By this time it is probable that the first stone structure, the Old Tower, had been built to protect the original castle entrance. The castle remained in the hands of the influential Carew family who built, in various phases, the strong medieval castle that stands today. Its history, however, was without major incident until about 1480, when Sir Edmund Carew disposed of it to Rhys ap Thomas. Rhys, basking in the gratitude of King Henry VII for the support he had given him after his landing at Milford Haven, was able to spend significant sums on the castle, and set about converting it into a home worthy of an influential Tudor gentleman. It was he who built the gatehouse which leads from the bailey into the outer ward of the castle.

From this small, square gatehouse, there is a fine view of the outside of the inner ward. The early 13th-century 'Old Tower' is abutted on the north by the late 13th-century hall and polygonal, projecting chapel tower; the rounded end of the Elizabethan wing lies beyond on the north corner. To the south lie the early 14th-century gatehouse and the late 13th-century south-east tower. Rhys ap Thomas later heightened some parts and much of the battlemented top is in fact his rather less-than-serious military work. The main gate to the inner ward is surprisingly unsophisticated; only an outer door, five murder holes in the vault above, an inner door with no less than three bar-holes and a portcullis.

Left: exterior view of the chapel tower and Perrot's north range from the outer ward.

The castle in the late 13th and early 14th century was in the hands of Sir Nicholas de Carew, who constructed many of the stone buildings which surround the small, compact inner ward. On the east (right) side is the ruinous three-storey tower in the corner which may have been balanced by a similar tower on the north-east, removed by a later Tudor wing. The early first-floor hall, built over a vaulted basement, and a fine projecting chapel tower, still stand intact. The fine windows on this courtyard side and the ornate fireplace inside the hall are the work of Sir Rhys ap Thomas. The chapel was housed on the first floor of the semi-octagonal chapel tower and has an attractive cross-ribbed vaulted ceiling, and a piscina and an aumbry (cupboard) on either side of the east window. Above the chapel was a private room.

The castle in the late 13th and early 14th century was in the hands of Sir Nicholas de Carew, who constructed many of the stone buildings which surround the small, compact inner ward. On the east (right) side is the ruinous three-storey tower in the corner which may have been balanced by a similar tower on the north-east, removed by a later Tudor wing. The early first-floor hall, built over a vaulted basement, and a fine projecting chapel tower, still stand intact. The fine windows on this courtyard side and the ornate fireplace inside the hall are the work of Sir Rhys ap Thomas. The chapel was housed on the first floor of the semi-octagonal chapel tower and has an attractive cross-ribbed vaulted ceiling, and a piscina and an aumbry (cupboard) on either side of the east window. Above the chapel was a private room.

The magnificent north wing was the last major addition to the castle. It was built by Sir John Perrot, to whom the castle was granted by the crown in 1558 after the downfall of Rhys ap Thomas's descendants. The building necessitated the destruction of the north-east tower and the northern curtain wall. The range consisted of five great rooms, the second floor being occupied by an enormous long gallery over 40m in length. The facade of the building is typically Elizabethan with two rows of great rectangular mullioned and transomed windows and two big oriel windows supported the massive tower-like semi-circular bases, Magnificent though it was, the building was not occupied for long. Sir John was convicted for treason in 1592 and died (of natural causes) in the Tower (of London). Thereafter the castle was let out to tenants, who probably found the great mansion too expensive to maintain, and the castle was abandoned about 1686.

View of the lesser hall from the inner ward.