History of Dover Castle

Dover Castle’s position, commanding the shortest sea crossing between England and the Continent, has given it immense strategic importance. The chalk of Castle Hill has been shaped and reshaped over the centuries into massive earthworks, ditches and mounds. Imposing walls and towers have been raised and networks of tunnels built beneath them. King Henry II began the building of the present castle in the 1180s, and over the next 800 years its buildings and defences were adapted to meet the changing demands of weapons and warfare.  

Aerial view of Dover Castle showing the various phases of the hilltop site
The castle’s massive ramparts and ditches may have originated in an Iron Age hillfort. At the centre are the Roman lighthouse and Anglo-Saxon church, and above them are the great tower and inner bailey

Before the Castle

Many centuries before King Henry II began the great stone castle here in the 1180s, its spectacular site above the famous white cliffs may well have been the site of an Iron Age hillfort.

The Romans built a lighthouse – one of the best-preserved in Europe – on the heights here after they invaded in AD 43, to guide ships into the harbour. The Anglo-Saxon church beside the lighthouse was once probably part of a Saxon fortified settlement. Restored in the late 19th century by Sir George Gilbert Scott and William Butterfield, it is the largest and finest Saxon building in Kent.


The recreated king’s chamber on the second floor of the great tower at Dover Castle, fitted out to evoke a late 12th-century royal palace
The recreated king’s chamber on the second floor of the great tower, fitted out to evoke a late 12th-century royal palace

The Medieval Castle

Immediately after his victory at Hastings in 1066, William the Conqueror strengthened the defences with an earthwork and timber-stockaded castle. From then on Dover Castle was garrisoned without interruption until 1958.

In the 1180s Henry II remodelled the castle, planning its great tower as a palace in which to entertain great visitors as well as a last redoubt for a strategically important castle. At 83 feet (25.3 metres) high, just under 100 feet (30 metres) square and with walls up to 21 feet (6.5 metres) thick, it has three floors of rooms, the topmost being state apartments for the king himself.

Within this magnificent showpiece, Henry could welcome and impress distinguished visitors to England – particularly noble pilgrims travelling to the new shrine in Canterbury Cathedral of Thomas Becket. The archbishop was slaughtered in front of the altar there by Henry’s household knights on 29 December 1170, ten years before the great tower was begun. On the second floor of the great tower is a chapel dedicated to Becket, with richly decorated stonework.

Building work continued in the first half of the 13th century under King John and Henry III, who completed the successive rings of defensive walls surrounding the great tower.

Artist's impression of the great siege of Dover Castle in 1216
An artist’s impression of the great siege of Dover Castle in 1216, showing French forces undermining the northern defences of the castle © Historic England (illustration by Peter Dunn)

Two Sieges

In 1216–17 these defences were twice put to the test when Dover withstood a long siege by an invasion force led by Prince Louis of France in support of English barons rebelling against King John. The fortress resisted ten months of bombardment by siege engines, undermining by tunnels and eventually hand-to-hand fighting.


Following the siege, John’s son Henry III added three powerful new gatehouses and a fortified spur extension to the castle. By the 1250s the medieval defences had assumed the extent and shape they retain today, a highly visible symbol of English royal power.

In October 1265 the castle was again besieged, this time by Prince Edward, Henry III’s son. Holding the castle was Eleanor de Montfort, the king’s sister and widow of rebel baron Simon de Montfort, who had been killed at the Battle of Evesham that summer. Attacked not only from outside but by royalist prisoners inside the castle, Eleanor negotiated an honourable settlement and was exiled to France.


View down passageway or caponier at Dover Castle, with cannon ranged left and right down its length
The upper level of the protected passage, or caponier, built as part of the outer defences to the north of the castle during the Napoleonic Wars

The Castle Transformed

After the Middle Ages Dover was continuously garrisoned into the 20th century. Although it declined in importance from the 16th century, it still hosted royal visits by Henry VIII, Elizabeth I and Charles I’s queen, Henrietta Maria.

From the 1740s onwards the medieval banks and ditches were reshaped as the castle was adapted for artillery warfare. Later in the 18th century, when England faced the threat of invasion from Napoleonic France, even more spectacular additions were made to the castle’s defences. To house the huge numbers of troops needed to man them, a network of tunnels was dug in from the cliff face for use as barracks.

The reconstructed coastal artillery operations room in the Second World War tunnels at Dover Castle
The reconstructed coastal artillery operations room in the Second World War tunnels at Dover Castle

Dover in Two World Wars

By 1905 advances in technology made it possible for coastal artillery around the harbour to be controlled from a central Fire Command Post built on the cliff edge. Its commanding position led the Admiralty to site a signal station on top of it in 1914, from which the Navy controlled the movement of all ships in and out of the harbour.


The Napoleonic tunnels were brought back into service in the Second World War, when they made their most notable contribution to British history. From 1939 they housed the command centre that controlled naval operations in the Channel. It was from here that in May 1940 Vice-Admiral Bertram Ramsay organised the extraordinary evacuation of British troops from Dunkirk, codenamed Operation Dynamo.

Over the next few years the tunnels were greatly extended to serve as both a hospital and a large combined headquarters, responsible for guarding the Straits of Dover and involved in preparing for the 1944 invasion of Europe.

Later, during the Cold War, this network of tunnels was transformed into the secret location of one of Britain’s Regional Seats of Government, with the role of organising life in the event of a nuclear attack.

Find out more

  • The Roman Lighthouse at Dover Castle

    Find out more about the Dover pharos, one of only three Roman lighthouses to survive from the whole of the former Roman Empire.

  • The Great Siege of Dover Castle

    Find out how, in 1216, Dover Castle and its stalwart defenders played a crucial part in preventing Prince Louis of France from becoming King Louis I of England.

  • Eleanor de Montfort and the Siege of 1265

    Caught up at the centre of a civil war, Eleanor de Montfort held Dover Castle against the king in 1265 after her husband and eldest son were killed in battle.

  • Fortress Dover and the First World War

    Use our virtual tour to explore a building at Dover Castle that played a vital role in safeguarding Dover as a garrison and naval base in the First World War.

  • Operation Dynamo: Things You Need to Know

    Find out the key facts about Operation Dynamo, the near-miraculous evacuation from Dunkirk in 1940, which was controlled from Dover Castle.

  • The Fall of France in 1940

    On 22 June 1940 the French government surrendered to Hitler, just six weeks after the Germans’ initial advance westwards. Find out why France collapsed so quickly.

  • Plans of Dover Castle

    Download these PDF plans of Dover Castle to see how this great fortress has evolved over time.

  • Buy the Guidebook

    Packed with plans, reconstructions and historic images, this guidebook tells the story of how the castle’s defences were adapted over 800 years.

  • More histories

    Delve into our history pages to discover more about our sites, how they have changed over time, and who made them what they are today.

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