Walmer 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 the local lords and communities, only taking a modest role in building and maintaining fortifications, and while France and the Empire remained in conflict with one another, 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 very limited in scale.

In 1533, Henry broke with Pope Paul III in order to annul the long-standing marriage to his wife, Catherine of Aragon and remarry.
Catherine was the aunt of Charles V, the Holy Roman Emperor, and he 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.

Walmer and the adjacent castles of Deal and Sandown were constructed to protect the Downs in east Kent, an important anchorage formed by the Goodwin Sands which gave access to Deal Beach, on which enemy soldiers could easily be landed.
The stone castles were supported by a line of four earthwork forts, known as the Great Turf, the Little Turf Bulwark, the Great White Bulwark of Clay and the Walmer Bulwark, and a 2.5-mile-long (4.0 km) 
defensive ditch and bank.
Collectively the castles became known as the "castles of the Downs" and cost the Crown a total of £27,092 to build.

Walmer was built between April 1539 and autumn 1540, by a team including Richard Benese as the surveyor, William Clement as the master carpenter, and Christopher Dickenson as the master mason.
It was initially garrisoned by a captain, two lieutenants, two porters, ten gunners and three soldiers, at an annual cost of £174.
It was probably equipped with a range of brass and cast-iron guns, along with arquebuses and bows for close defence.
In 1597, a report listed the castle's artillery as comprising a cannon, a culverin, five demi-culverins, a saker, a minion and a falcon.
Walmer 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 the local lords and communities, only taking a modest role in building and maintaining fortifications, and while France and the Empire remained in conflict with one another, 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 very limited in scale.
In 1533, Henry broke with Pope Paul III in order to annul the long-standing marriage to his wife, Catherine of Aragon and remarry. Catherine was the aunt of Charles V, the Holy Roman Emperor, and he 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.
Walmer and the adjacent castles of Deal and Sandown were constructed to protect the Downs in east Kent, an important anchorage formed by the Goodwin Sands which gave access to Deal Beach, on which enemy soldiers could easily be landed. The stone castles were supported by a line of four earthwork forts, known as the Great Turf, the Little Turf Bulwark, the Great White Bulwark of Clay and the Walmer Bulwark, and a 2.5-mile-long (4.0 km) 
defensive ditch and bank. Collectively the castles became known as the "castles of the Downs" and cost the Crown a total of £27,092 to build.
Walmer was built between April 1539 and autumn 1540, by a team including Richard Benese as the surveyor, William Clement as the master carpenter, and Christopher Dickenson as the master mason. It was initially garrisoned by a captain, two lieutenants, two porters, ten gunners and three soldiers, at an annual cost of £174. It was probably equipped with a range of brass and cast-iron guns, along with arquebuses and bows for close defence. In 1597, a report listed the castle's artillery as comprising a cannon, a culverin, five demi-culverins, a saker, a minion and a falcon.
Walmer Castle