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
Geography of Dorset South Haven Point, is narrow, less than 0.25 miles across. Its shoreline is irregular and heavily indented with numerous small inlets and channels, between which many small peninsulas extend out into the body of the harbour. The harbour also houses several small islands, the largest of which is Brownsea Island. Chesil Beach is a barrier beach on the southwest coast of the county. It is long and stretches between West Bay and the Isle of Portland, although the name Chesil Beach is often only applied to the stretch south-east of Abbotsbury, where it is separated from the land behind it