Brownsea Castle the castle also has four cannons, probably dating from the 17th or early 18th century. The castle is protected under UK law as a Grade II listed building. Brownsea Castle Brownsea Castle, also known historically as Branksea Castle, was originally a Device Fort constructed by Henry VIII between 1545 and 1547 to protect Poole Harbour in Dorset, England, from the threat of French attack. Located on Brownsea Island, it comprised a stone blockhouse with a hexagonal gun platform. It was garrisoned by the local town with six soldiers and armed with eight artillery pieces. The castle remained in use after
Brownsea Castle of the 20th century, using it to house his collection of antique musical instruments. Brownsea Castle was purchased by Mary Bonham-Christie in 1927. She allowed the property to fall into disrepair and by the time of her death in 1961 it was in a very poor condition. It was then purchased by the National Trust and leased to the John Lewis Partnership, who restored it over many years. In the 21st century it is still used by the Partnership as a corporate hotel for their employees and retired staff. Brownsea Castle was built as a consequence of international tensions between