Pendennis Castle and the Fal estuary, Cornwall

History of Pendennis Castle

Pendennis Castle is one of England’s finest surviving coastal fortresses. Together with the fortress at St Mawes, Pendennis guarded the anchorage of Carrick Roads and the port towns below for over 400 years. The castle began as a gun fort in the mid-16th century. Bastioned defences were added in the 1590s following the threat of Spanish invasion and were periodically updated, notably during the Second World War when the guns again saw action.

Henry VIII’s circular gun tower, begun in about 1540; a round brick tower set on a grassy slope.
Henry VIII’s circular gun tower, begun in about 1540. The building on the right is a later Tudor addition

Henry VIII’s Artillery Fort

Pendennis Castle was built from 1539 to 1545 when England faced a possible invasion from the united powers of Catholic Europe. To defend against this, Henry VIII implemented a national programme of military and naval preparations, including new coastal artillery forts. These were equipped with guns to shatter enemy warships and troop transports that might attempt to capture English ports.[1]

The important anchorage of Carrick Roads, a deep estuary at the mouth of the river Fal, was a perfect location for an enemy to establish a base. To protect it, Henry built gun forts on opposite shores, at Pendennis and St Mawes. Pendennis Castle had a circular design that allowed all-round fire from guns mounted at several levels.

The fort was fully garrisoned (guarded) by up to 100 men only when there was an imminent threat, notably during the planned Spanish invasions of 1574, 1579, 1588 (the ‘Great Armada’) and 1596–7. On the last occasion, a Spanish fleet intended to land troops at Pendennis and capture Carrick Roads. The attack never came, but the threat forced Elizabeth I to review the defences.[2]   

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Aerial view of Pendennis, looking south-east. Little Dennis can be seen on the top left of the land mass and the bastions surrounding the castle are clearly visible.
Aerial view of Pendennis, looking south-east. Little Dennis can be seen on the top left of the land mass and the bastions surrounding the castle are clearly visible

The Bastioned Fortress

In 1597 the soldiers and courtiers Sir Nicholas Parker, Sir Ferdinando Gorges and Sir Walter Raleigh surveyed the defences of Pendennis. By 1600, the engineer Paul Ive had enclosed Henry VIII’s castle within a much larger fortress to defend the whole of Pendennis headland.[3] It was an elongated pentagon in plan, defined by a high rampart and ditch, with a bastion projecting at each angle.

A large triangular area of the new fortress (a salient) overlooked Pendennis Point, where a smaller fort included the earlier gun tower known as Little Dennis. The bastions had heavy guns to protect against attack by land and sea. They also defended the fort against a close assault by land, to which the circular form of Henry VIII’s castle was vulnerable.

Reconstruction of Pendennis as it may have appeared during the siege of 1646
Reconstruction of Pendennis as it may have appeared during the siege of 1646
© Historic England (illustration by Ivan Lapper)

The Siege of Pendennis, 1646

Between 1625 and 1630 England made a catastrophic attempt to influence the course of the Thirty Years War in continental Europe, mainly in opposition to Spain. This prompted improvements to Pendennis and in 1627, the engineer Sir Bernard Johnson constructed a new rampart and ditch (the Hornwork) across the peninsula, replacing a neglected Tudor earthwork and strengthening the land defences to the north.[4]

Pendennis was tested during the First Civil War (1642–6), when Falmouth was an important port for King Charles I’s army. In 1646 Pendennis was one of the last Royalist strongholds to hold out against the Parliamentary army; about 1,000 soldiers and their dependents endured a five-month siege, agreeing an honourable surrender in August when their food supplies ran out.[5]

Although there were no major events at Pendennis after 1646, continuing warfare with the Dutch and the French ensured that a small garrison was maintained, on and off, and a new guard barracks and gateway built in about 1700.

The Pendennis Artillery Volunteers in the Pendennis castle, c.1800
The Pendennis Artillery Volunteers in the castle, c.1800
© Council of the National Army Museum (painting by Charles Tomkins)

Georgian Modernisation

In 1714, coastal defences were reviewed, and the engineer Colonel Christian Lilly reported Pendennis ‘neglected’ and ‘in a very ruinous condition’. His recommendations for repairs were implemented from 1732 to 1739; the old rampart was re-formed, new guns were installed, and new buildings erected, including a storehouse, gunpowder magazine (store) and gunners' barracks.[6]

From 1775 to 1780, in the American War, the locally raised Miners’ Militia garrisoned Pendennis and new barracks were built. During the long wars with Napoleonic France (1793–1815) the garrison became permanent and the defences were strengthened by five raised gun batteries (cavaliers) on the rampart overlooking the landward approaches. A new sea battery, Half Moon Battery, was built outside the fort on the south, while a host of barracks, a hospital and store buildings were erected both inside the fortress and on Hornwork Common to the north.[7]

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The sunken magazine of One-Gun Battery, with the gun concealed within a concrete well and grassy banks.
The sunken magazine (foreground) and deep gun put (centre) of One Gun Battery. The original six-inch gun was installed in 1895 but removed by 1913; the gun on display today shows the original firing position.

Decline and Rearmament

After the defeat of Napoleon at Waterloo in 1815, Pendennis was neglected and many of the temporary buildings were removed. By the late 1850s, however, England and France were rivals again in a race for military and naval advantage. More powerful guns were installed at Pendennis from 1854,[8] notably at Half Moon Battery and at Crab Quay, on the east side of the headland.

Yet the fortress received little attention in the nationwide programme of fort-building in the 1860s, being considered a lower strategic target for the enemy than many other locations around the coast.

Nonetheless, the outdated defences were gradually improved from 1880 to 1900, a period of revolutionary change in military technology. The first major development was a submarine minefield laid across the entrance to Carrick Roads in 1885, with mines that could be detonated remotely.

But it was Falmouth’s designation as a Defended Port in 1887[9] that resulted in many new defences for the estuary, commanded from Pendennis Castle. These comprised breech-loading guns (replacing the older, muzzle-loading guns), accurate range-finders, searchlights to aid night fighting and telephones and electricity to enable efficient communication. Six-inch guns – those firing sizeable shells with a six inch diameter – were intended to engage warships from new positions in One Gun Battery inside Pendennis and from Half Moon Battery, while light quick-firing 6- and 12-pounder guns to counter fast torpedo boats were fitted in East Bastion,[10] Carrick Mount Bastion[11] and Crab Quay.

Such intricate defences required a permanent staff and in 1902 new barracks were built at Pendennis for the 105th Regiment Royal Garrison Artillery.[12] Many other new buildings included a War Signal Station on the roof of the Henrician castle to control shipping movements.[13]

A table within the Battery Observation Post arranged as it may have been during the Second World War with a telephone, lantern and papers and maps.
The Battery Observation Post, arranged as it may have been during the Second World War. It was built to control the six-inch guns of Half Moon Battery

The World Wars

During the First World War (1914–18) Pendennis was the command centre of coast artillery defences for west Cornwall.[14] Key defence points and trenches protected it and thousands of troops came for training before going to war in France and Belgium. The Royal Navy used the anchorage for convoys, minesweepers and anti-submarine vessels.[15]

In 1939 Pendennis resumed control of coast defences.[16] The threat from torpedo boats was countered by twin 6-pounder and 12-pounder guns, while long-range defence against ships came from guns in new covered positions at Half Moon Battery. From 1943 these were the latest 6-inch mark 24 models, operating with precision under radar control. Huts and temporary buildings were erected, the Pendennis Fire Command Post enlarged (from which the Fire Commander could control all his guns), and a Battery Plotting Room was established to co-ordinate target data coming from all sources.


Find out more about Pendennis during the first world war

After the war Pendennis Castle continued to be used for training until 1956 when the Coast Artillery Branch of the Army was disbanded. A year later, it was returned to the guardianship of the Ministry of Works for opening to the public.

Visitors to the castle today experience a fascinating stroll through a complex history of conflict. Perched above the sea with dramatic panoramic views to Falmouth, across Carrick Roads and out into the open sea, Pendennis Castle stood fast for over four centuries of intermittent warfare and frequent threats of attack or invasion. There is no more dramatic reminder of the turbulent history of our islands.


About the Author

Paul Pattison is a landscape archaeologist, historian and military specialist at English Heritage.

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    For Henry VIII’s preparations see HM Colvin (ed), The History of the King’s Works, vol 4, 1485–1660, part 2 (London, 1982), 367–83; BM Morley, Henry VIII and the Development of Coastal Defence (London, 1976), 8–9; and A Saunders, Fortress Britain: Artillery Fortification in the British Isles and Ireland (Liphook, 1989), 34–47.
    R Linzey, Fortress Falmouth: A Conservation Plan for the Historic Defences of Falmouth Haven, vol 2 (London, 2000), 5–13.
    British Library, Harleian MS 6252, fol 41v (John Norden's plan of Pendennis); British Library, Cotton Augustus I.i, fol 43 (‘a colour plan of Falmouth Fort [Pendennis Castle]’, c 1590–98); The National Archives (TNA), MPF 263 (John Norden’s plan of 1603); TNA, SP 12/266, fol 101, 27 Feb 1598: the defences were well under way by the time Sir Nicholas Parker wrote to Lord Burghley about them; TNA, SP 12/275, fol 75, 16 Aug 1600: the works were almost complete when Sir Nicholas Parker wrote to the Privy Council asking for guns.
    TNA, SP 16/65, fol 54: a warrant was issued in May 1627 to Bernard Johnson granting permission to appoint Michael Lambert as his deputy at the works at Pendennis; TNA, SP 16/73, fol 76: Robert Killigrew wrote to Secretary of State Edward Conway on 6 Aug 1627, describing the works under way, including the ‘Horne worke’.
    M Coate, Cornwall in the Great Civil War and Interregnum 1642–1660 (Oxford, 1963), 194–5, 207–11 and 215–19.
    British Library, Kings MS 45: Reports of the present state and condition of His Maiesties fortifications, buildings, and artillery in the South Western Department of England, otherwise call’d ‘Plymouth Division or District’, with surveys, plans, proposals, and estimates for ‘remedying the deffects thereof’, &c., begun 1 Geo. I by direction of the Ordnance Office, and executed by Col. Christian Lilly, Engineer of the Ordnance (1714–17).
    Linzey, op cit, 40–42.
    Ibid, 48–9.
    TNA, CAB 7/6 (Carnarvon Commission: Consultative Committee Report on fortification and armament of military and mercantile ports, Aug 1887).
    TNA, WO 78/5071 (Plymouth and Falmouth Area: Pendennis Castle: no. 3 bastion quick-firing battery record drawings, 1904)
    TNA, WO 78/4094 (Falmouth, Pendennis Castle: no. 2 bastion emplacement for 2 x 12-pounder quick-firing guns, 1902).
    TNA, WO 78/2757 (Pendennis Castle, Falmouth: record plans of barracks and buildings, 1904).
    Linzey, op cit, pp 58, 88.
    TNA, WO 33/578 (South-West Coast Defence Scheme for Falmouth Fortress, 1911).
    Linzey, op cit, 64–9.
    TNA, WO 192/275 (Half-Moon Battery record book); TNA, WO 192/278 (Falmouth Fire Command record book).