Pembroke castle stands on the river Cleddau, in the town of Pembroke. The castle is the original seat of the earldom of Pembroke. In 1093 Roger of Montgomery built the first castle on this site. A century later the castle was given to William Marshal by Richard I, and he rebuilt the castle in stone creating most of the structure that remains today. In the late 13th century additional buildings were added, including a new Great Hall. A 55 step spiral stairwell was created that led down to a large limestone cave , known as Wogan Cavern beneath the castle, this was fortified with a wall barred gateway and arrowslits. It may have served as a boathouse or a sallyport to the river where cargo and people could have been transferred. The outer walls of the castle are 16ft (5mtrs) thick in places and constructed from Siltstone ashlar. Although the castle is in the Norman style, it is more accurately described as a Linear fortification.
The castle stands on a site that has been occupied since Roman times. The original earth and wood castle resisted several Welsh attacks and sieges over the years, eventually establishing itself at the heart of the Norman controlled lands of southwest Wales. Later the castle was used as an important base for the Norman invasion of Ireland. William Marshal who received the castle and title Earl of Pembroke in 1189, was succeeded by each of his five sons. However all of Marshal’s son’s died childless so in 1247 the castle was inherited by William de Valence, a half brother of Henry III. The castle became de Valance’s military fighting base during the conquest of North Wales by Edward I between 1277 and 1295. The castle next passed to the Hastings family, after the death of William de Valence’s son. In 1389, 17 year old John Hastings died in a jousting accident, and so ended a line of inheritance stretching back 250 years. The castle then reverted to Richard II who granted short tenancies.
Eventually the castle was granted to Jasper Tudor by his half brother Henry VI in 1452. Tudor brought his widowed sister in law, Margaret Beaufort, to Pembroke where she gave birth to her only child, the future king Henry VII of England, (born 1457)