Pembroke Castle is a medieval castle in the centre of Pembroke, Pembrokeshire in Wales. The castle was the original family seat of the Earldom of Pembroke. A Grade I listed building since 1951, it underwent major restoration during the early 20th century. In 1093, Arnulf of Montgomery built the first castle at the site when he fortified the promontory beside the Pembroke River during the Norman invasion of Wales.