 Netley Abbey had been recently dissolved by Henry, and material from the site was reused to build the castle.William Paulet, later the Marquess of Winchester, was in charge of the construction, which took place in either 1542 or 1544 and Henry granted him various estates to pay for the support of the fort and its garrison.The castle took the form of a central keep, across with deep embrasures along the battlements, and a gun platform on either side; its design resembled that at nearby Southsea.