Pembroke Castle is a medieval fortress in Pembroke, South Wales. It was the seat of the Norman Earls of Pembroke for centuries.

Pembroke Castle was begun in 1093 by Arnulf de Montgomery on a promontory near the Pembroke River as part of the initial Norman conquest of Wales. He made Gerald of Windsor, who built Carew Castle, its castellan. Today, it is located in what became known in south Wales as ‘little England’ in that this region has been ruled by the English since that early date.

The castle began as a typical motte and bailey structure with a rampart and palisade. It was rebuilt in the 12th century in stone by William Marshal, who was not only the Earl of Pembroke but also the Marshal of England. He had acquired the castle in 1189 through marriage to Isabel de Clare, daughter of Gilbert de Clare, the former Earl of Pembroke known also as Strongbow. The remains of William’s constructions include the huge round keep with its domed roof. The castle was again refurbished in the 13th century to include a new great hall and domestic buildings in the inner ward.

A 55-step spiral staircase leads down to a large limestone cave beneath the castle, known as Wogan Cavern. The cave, which was created by natural water erosion, in medieval times was fortified by a wall, a barred gateway, and arrow slits. It may have served as a boathouse or a sallyport to the river where cargo or people could have been transferred or escaped if the castle was under siege.

Pembroke was never taken or even attacked until the English Civil War. It surrendered to Cromwell’s forces, who subsequently made it indefensible, even to the point of encouraging townspeople to take the stones and repurpose them.