Southsea Castle

Southsea Castle, historically also known as Chaderton Castle, South Castle and Portsea Castle, is an artillery fort originally constructed by Henry VIII on Portsea Island, Hampshire, in 1544. It formed part of the King's Device programme to protect against invasion from France and the Holy Roman Empire, and defended the Solent and the eastern approach to Portsmouth. The castle had a square central keep, two rectangular gun platforms to the east and west, and two angled bastions to the front and rear, and was an early English example of the trace italienne-style of fortification popular on the Continent. The Cowdray engraving of the Battle of the Solent in 1545 depicted Henry VIII visiting the castle. Despite several serious fires, it remained in service and saw brief action at the start of the English Civil War in 1642 when it was stormed by Parliamentary forces.

The castle was expanded in the 1680s by Sir Bernard de Gomme and, after a period of neglect in the 18th century, was redesigned again in 1814 during the Napoleonic Wars. After a brief period of use as a military prison in the 1840s, the fortification was expanded in the 1850s and 1860s with additional gun batteries on the east and west sides. The defences were upgraded throughout the century due to the fears of a French invasion and formed part of the plan for defending Portsmouth during the First World War. In the interwar years some of the fortifications were stood down, but the castle saw service again in the Second World War, when it was involved in Operation Grasp, the seizure of French naval vessels in Portsmouth harbour. In 1960, Southsea Castle, by now obsolete, was sold to Portsmouth City Council. It was restored to its pre-1850 appearance and opened as a tourist attraction, receiving over 90,000 visitors from 2011–12.

Southsea Castle was built as a consequence of international tensions between England, France and the Holy Roman Empire in the final years of the reign of King Henry VIII. Traditionally the Crown had left coastal defences to local lords and communities, only taking a modest role in building and maintaining fortifications, and while France and the Empire remained in conflict, maritime raids were common but an actual invasion of England seemed unlikely. Modest defences based around simple blockhouses and towers existed in the south-west and along the Sussex coast, with a few more impressive works in the north of England, but in general the fortifications were limited in scale.

In 1533, Henry broke with Pope Paul III over the annulment of his long-standing marriage to Catherine of Aragon. Catherine was the aunt of Charles V, the Holy Roman Emperor, who took the annulment as a personal insult. This resulted in France and the Empire declaring an alliance against Henry in 1538, and the Pope encouraging the two countries to attack England. An invasion of England appeared certain. In response, Henry issued an order, called a "device", in 1539, giving instructions for the "defence of the realm in time of invasion" and the construction of forts along the English coastline. The immediate threat passed, but resurfaced in 1544, with France threatening an invasion across the Channel, backed by her allies in Scotland. Henry therefore issued another device to further improve the country's defences, particularly along the south coast.

The castle was built on the southern end of Portsea Island to protect a deep-water channel running through the Solent to the royal naval base at Portsmouth. Work began in early 1544, under the overall direction of Sir Anthony Knyvett, the Governor of Portsmouth, supported by Richard Cawarden, the Dean of Chichester, and John Chatterton, the captain of the Portsmouth garrison; Thomas Bertie was appointed as the master mason. It is uncertain who designed the castle, although Knyvett described it as being "of his Majesty's own device", which typically indicated that the King had taken a personal role. The design abandoned the earlier use of semi-circular bastions, which could not be fully covered by flanking fire from the supporting walls, and instead used an angular design, forming an early, if imperfect, adoption of the trace italienne-style of fortification already in use in Continental Europe.

The work was carried out quickly due to the risk of a French attack, and by July two brass saker guns were mounted on the site. It cost at least £3,100, £1,300 of which came from the proceeds of the Dissolution of the Monasteries, with chalk, stone and timber being brought across from the neighbouring Isle of Wight. The castle was completed by October and formed a fortification with a square keep, rectangular gun platforms to the east and west, and angled bastions to the front and rear. Chatterton was appointed the new captain, with a team of eight soldiers, twelve gunners and a porter. The castle was well-armed, with seven brass artillery pieces - a culverin, demi-culverin, cannon and demi-cannon - and eight iron guns.

The French invasion emerged in 1545, when Admiral Claude d'Annebault crossed the Channel and arrived off the Solent with 200 ships on 19 July, landing troops on the Isle of Wight. Henry's fleet made a brief sortie, resulting in the Battle of the Solent, in which the English flagship, the Mary Rose, was lost, before retreating safely behind the protective fortifications. Henry was present in Portsmouth at the time and the Cowdray engraving of the battle depicts him visiting Southsea Castle. The French expedition moved further on along the coast on 25 July, bringing an end to the immediate invasion threat, but Henry gave orders for additional improvements to the fortification to be made that summer, including the construction of stone flankers and timber caponiers, to guard against a potential infantry attack. Edward VI spent a night at the castle in 1552 while inspecting the defences of Portsmouth.

In the early 1600s, England was at peace with France and Spain and as a result the coastal defences received little attention; a survey found Southsea Castle to be "verie ill prepared for defence", with no guns mounted along the walls or any stocks of powder. In March 1626, a serious fire broke out that destroyed the interior of the keep and generated panic among the ships moored nearby. The damage was not repaired until 1635, when 210 loads of timber was sent from the New Forest for use in the work. Another serious fire then broke out in 1640, causing damage to the lodgings and store rooms.