A Norman castle built by William Marshall, the pre-eminent English knight of the Middle Ages, around 1300. The great keep is still standing to a height of 80 feet. Pembroke Castle is the reputed birthplace of Henry VII.

The castle was founded in the 2nd half of the 13th century, although the lordship de Rupe (rock) can be traced back to about 1200. An earlier fortress may have existed here, but the prominent D-shaped tower on this isolated rocky outcrop is thought to have been built by Adam de Rupe. The family had played an important role in the English settlement of Pembrokeshire and owned considerable territory in the northern areas. Roch Castle was doubtless built as one of the outer defences of "Little England" or "Landsker" for it is near the unmarked border for which centuries has separated the English and Welsh areas of Pembrokeshire.

The ruins of Carew Castle stand in majestic splendour on the low banks of the river Carew, near Pembroke. Gerald of Windsor erected a Norman motte and bailey castle here about 1100, building on a still earlier Iron Age fort. The lovely present castle is based on a 13th century structure begun by Sir Nicholas de Carew. Three towers and the chapel survive from Carew's time, but more obvious are the early Tudor additions of Sir Rhys ap Thomas, including the gatehouse.

13th century castle walls remain along with a ruined gate and a tower. The town's defensive walls are well preserved.