(This article is about the former artillery fort in the centre of Cowes. For the stately home built by John Nash, see East Cowes Castle.) Cowes Castle, also known as West Cowes Castle, is a Device Fort in Cowes on the Isle of Wight. Originally built by Henry VIII in 1539 to protect England against the threat of invasion from France and the Holy Roman Empire, it comprised a circular bastion, flanking wings and a keep, and in 1547 it housed 17 pieces of artillery. With its companion fortification at East Cowes, the castle overlooked the entrance to the River Medina, an important anchorage. The invasion threat passed but the fortification continued in use until the middle of the 19th century, very briefly seeing action in 1642 during the English Civil War.