Portland Castle is one of the Device Forts, also known as Henrician Castles, built in 1539 by Henry VIII on the Isle of Portland to guard the natural Portland anchorage known as the Portland Roads. The castle lies in the far north of the island, in the village now called Castletown, near Fortuneswell. The castle is under the care of English Heritage.
The castle artillery forts stretched all around the Kent coast, along the south coast of England, down to Lands End. Strategic sites were chosen protecting possible landing points of an invasion. The area today known as Portland Harbour was a weak point, and Portland castle was built. The entire harbour fell under artillery range from Portland Castle and nearby Sandsfoot Castle.
Portland Castle has a low profile offering less of a target, with a traditional rounded wall facing the sea, designed to deflect incoming ordnance. The land side was moated.
The castle was bolstered ready to repel the attempted invasion by the Spanish Armada in 1588. In the event the Royal Navy fended off the Spanish fleet in the famous Battle of Portland just east of the isle of Portland.
Portland Castle experienced its only real action during the English Civil War 1642-1649. Being an historic Royal Manor, Portland naturally supported King Charles and was a Royalist stronghold. Nearby Weymouth - a merchant town - firmly backed Cromwell’s Parliamentarians and a succession of battles and ruses saw Portland Castle captured and recaptured several times. Despite being hopelessly undermanned and inadequately armed, the Royalists managed to keep the island out of Cromwellian hands for all but two brief periods of the war. By 1645, after repeated attacks only Portland, Corfe and Sherborne remained in Royalist hands. When defeat finally came in 1646 Portland’s surrender was bloodless, and on remarkably generous terms.
On the restoration in 1660, Charles II rewarded Portland’s loyalty in the Civil War by a special Royal Grant Fund, giving back to the Islanders royalties on stone taken from the crown quarries. The Grant is still made today.
The castle again stood by during action in the Anglo-Dutch war with the Battle of Portland, an bloody but indecisive three day sea battle close to the Island coast.
Portland castle was armed for the last time during the Napoleonic Wars.