Mersea Fort: A Tudor Coastal Artillery Fort in England
Site at a Glance
- Rating
- 4.2
- Popularity
- Very Low
- Country
- United Kingdom
- Primary era
- Early Modern
- External website
- Open
- Eras represented
- Early Modern, Modern
- Civilizations
- British, English
- Site type
- Military
- Remains
- Fort
On this page12 sections
History
Mersea Fort, also known as Cudmore Grove Blockhouse, is a Tudor artillery fort in East Mersea, United Kingdom, established in 1543 during the final years of Henry VIII’s reign. Built as part of the King’s Device programme, the royal scheme for preparing England’s coast against invasion, it defended the entrance to the River Colne and the river route towards Colchester.
Tudor coastal defence
The fort formed part of a group of new coastal works at Mersea, St Osyth, and Brightlingsea. Richard Lee and Richard Cawarden directed the construction, while the wider programme of coastal works in Essex was estimated to cost £2,717. The immediate threat came from France and the Holy Roman Empire, a politically fragmented central European polity ruled by Emperor Charles V. Henry VIII’s dispute with the papacy over the annulment of his marriage to Catherine of Aragon contributed to the alliance that prompted this defence programme.
Mersea Fort was decommissioned in 1552, but Mary I later recommissioned it. It returned to military use in 1588 during the threat from the Spanish Armada and was brought back into service in 1631 in response to the activities of Dunkirker privateers. A 1586 survey, however, found the fort abandoned by the military. Its defences were in poor condition, dirt clogged the gun barrels, and an elderly woman had taken possession of the site.
The fort and the oyster fisheries
The fort also accommodated an admiralty court, a maritime court dealing with matters such as fisheries, shipping, and coastal jurisdiction. The court supervised the valuable oyster fisheries along the East Mersea coast. After Colchester introduced oyster-trade regulations in 1566, the court met at the fort when necessary, demonstrating the town’s authority across the estuary.
The admiralty court continued to meet there during the seventeenth century, although political disorder made the oyster regulations increasingly difficult to enforce. Legislation passed in 1758 created a court of conservancy to regulate and protect the oyster stocks. The court was officially intended to sit at Mersea Fort, but the ruinous condition of the building led it to meet at Colchester’s Moot Hall instead. An annual ceremony later took place at the nearby Mersea Stone, with local dignitaries and extensive eating and drinking. Reform of the oyster legislation in 1870 abolished the former court structure and ended the fort’s long institutional connection with the fishery.
Civil War and Commonwealth service
Mersea Fort saw no action during the First English Civil War. After Parliament’s victory in 1646, its garrison was demobilised. The outbreak of the Second English Civil War in 1648 changed its position. General Thomas Fairfax, a senior Parliamentary commander, seized the fort before Royalist forces could occupy it. Because it controlled the river supply route to Royalist-held Colchester, 300 Royalist soldiers tried unsuccessfully to recapture it.
Captain William Burrell took command after the Parliamentary capture. The fort retained guns and ammunition against renewed rebellion and was staffed by 36 men. In July 1650, a squadron of horsemen and 50 infantrymen temporarily reinforced the garrison. Repairs began in 1651 and included new accommodation for the gunners.
Following an invasion scare in 1655, the fort temporarily held Royalists suspected of planning an insurgency against Oliver Cromwell’s Commonwealth government. Cromwell later ordered its demobilisation to reduce defence expenditure and instructed Burrell to dismantle it. Practical difficulties and opposition from the landowner prevented the order from being carried out.
Later military use and investigation
By the eighteenth century the fort had become ruinous. It was recommissioned during the Napoleonic Wars at the beginning of the nineteenth century, when a new battery facing the sea was constructed. The fort was abandoned again after that period. A sea wall built along the coast early in the nineteenth century cut through its south-eastern side and extensively damaged the fortification.
A defensive pill-box, a small fortified position for weapons and troops, was built at the site during the Second World War. The remains were surveyed in 1982 and excavated between 2002 and 2003. Those investigations examined timber structures exposed by coastal erosion. The surviving ruins, including the earthworks, are protected under UK law as a scheduled monument.
Remains
Mersea Fort stood on salt marshland south of the River Colne, positioned at the entrance to the estuary. Its main defences formed a triangular earthwork about 300 feet, or 91 metres, between each pair of corners. A defensive ditch surrounded the fort and was crossed by a drawbridge. The earthworks were strengthened with maunds, round baskets filled with earth, while circular artillery bastions projected from the three corners.
Earthworks and internal buildings
Triangular earthworks
The triangular enclosure organized the fort around a central courtyard. Each corner bastion, a projecting platform for guns, could accommodate up to four artillery pieces. The fort’s original garrison consisted of a captain, a lieutenant, two soldiers, a porter, and between three and six artillery gunners. Buildings within the courtyard provided their accommodation.
Jetty and timber remains
A nearby jetty was probably associated with the fort, although its precise use is not known. Coastal erosion later exposed timber structures, which archaeologists examined during the excavations of 2002 and 2003. The remains survive in a ruined condition, with the earthworks forming the principal surviving features.
Artillery positions
Tudor artillery
In 1648 the fort contained five artillery pieces: two culverins, two sakers, and one drake. These were types of early modern cast guns, with the names referring to different forms and sizes of artillery. Their positions were integrated into the corner bastions and the wider earthwork defences.
Napoleonic battery
The sea-facing battery built during the Napoleonic Wars carried six 24-pounder guns. Each gun weighed 10.9 kilograms. The later sea wall cut through the south-eastern side of the earthworks, causing extensive damage to the fortification and affecting the survival of its physical remains.
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