Sandown Castle, Isle of Wight

Device Fort built at Sandown on the Isle of Wight

Sandown Castle was a Device Fort built at Sandown on the Isle of Wight by Henry VIII in 1545 to protect against the threat of French attack. Constructed from stone with angular bastions, its design was a hybrid of Italian military architectural thinking with traditional English military design. The site was raided by a French force that summer while the fortification was still being constructed. The site suffered from coastal erosion and the castle was demolished in 1631.

Sandown Castle was built as a consequence of international tensions between England, France and the Holy Roman Empire in the final years of the reign of King Henry VIII. Traditionally the Crown had left coastal defences to the local lords and communities, only taking a small role in building and maintaining fortifications, and while France and the Empire remained in conflict with one another, maritime raids were common but an actual invasion of England seemed unlikely. Modest defences, based around simple blockhouses and towers, existed in the south west and along the Sussex coast, with a few more impressive works in the north of England, but in general the fortifications were very limited in scale. In 1533, Henry then broke with Pope Paul III to annul the long standing marriage to his wife, Catherine of Aragon and remarry. This resulted in France and the Empire declaring an alliance against Henry in 1538, and the Pope encouraging the two countries to attack England. Henry responded in 1539 by ordering, through an instruction called a "device", the construction of fortifications along the most vulnerable parts of the coast. The immediate threat passed, but resurfaced in 1544, with France threatening an invasion across the Channel, backed by her allies in Scotland. Henry therefore issued another device in 1544 to further improve the country's defences, particularly along the south coast.

Built between April and September 1545 to protect the south east coast of the Isle of Wight, Sandown Castle overlooked Sandown Bay. It was constructed by the Italian engineer Giovanni Portinari, the surveyor William Ridgeway and the captain of labourers, John Portinar, at a cost of £2,400. Designed around a central courtyard, it had a square tower and two angular bastions on one side, and a circular bastion looking out to sea. The rear of the stone defences was protected by a moat, and the castle had a wooden pier for boats to dock at. The angular bastions echoed contemporary Italian thinking on military architecture, and may have been influenced by Richard Lee, the King's Surveyor of Works, as well as by Portinari's own continental background. Despite being relatively advanced for an English fortification, the castle did not feature the more fashionable Italianate "arrow head" bastion design used at nearby Yarmouth Castle and has been critiqued by historians: Andrew Saunders describes it as an imperfect "hybrid" of English and continental ideas, John Hale as a timid, confused flirtation with modern designs. Before the castle could be completed, however, the French attacked. Admiral Claude d'Annebault crossed the Channel and arrived off the Solent with 200 ships on 19 July, where the local authorities feared Sandown Castle might be the target of a night attack. 2,000 French soldiers men landed on the Isle of Wight and attacked Sandown, where labourers were still present.

By the 17th century, coastal erosion had undermined the castle's walls. In 1627, Charles I announced that he would repair the fortification but instead the ruins were dismantled in 1631 by Sir John Oglander.