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 fallen into disuse. In 1726 the castle was converted into a private residence by William Benson, despite complaints from the town of Poole. Benson and the subsequent owners extended the original blockhouse to form a country house, landscaping the surrounding island to create ornamental gardens and lakes. The 19th century saw continued building work by the castle's occupants, including the entrepreneur Colonel William Waugh, who erected various Jacobethan-styled extensions. A serious fire in 1896 gutted the castle, which was restored by Major Kenneth Robert Balfour. The wealthy stockbroker Charles Van Raalte led a lavish lifestyle at Brownsea at the start