The coastal town of Calais was first fortified in 13th century, when a castle and town walls were built. In 1346, the English laid siege to Calais, finally starving the place into submission after an 11 month siege. They cut the town off from supply ships by building a wooden tower, known as the Lancaster Tower, at the entrance to the harbour.
In the 15th century as artillery grew in importance, the Lancaster Tower was surrounded by a perimeter wall and two lower towers mounting guns. This work became known as Fort Risban. To the west of the town at Newnham Bridge were some sluice gates controlling the river Hames. When these sluice gates were closed, the river water was diverted to flood the land to the south of the town. This system could be used to prevent an attack on Calais from the land.
In the early 16th century the English built a fort to protect these vital sluices. This fort, called Fort Nieulay, was square with four stone towers. In 1556, as the threat of a French attack was looming over Calais, the engineer John Rogers'became surveyor of works at Calais.
However, there was little money available for large-scale projects and the only adaptations for artillery were a double ditch and few earthen demi-lunes'in front of the medieval walls.
In 1558 the French took Calais by surprising the defenders of Fort Nieulay, so that the sluices were not closed. During the 1560s they had the Italian engineer Castriotti build a citadel'in the west by putting a bastioned'front across the town. In 1596 the Spanish took the defenders of Fort Nieulay by surprise and captured Calais. The Spanish strengthened Fort Nieulay by reducing the height of the towers and enclosing them in large earthen bastions.
When Calais was returned to France in 1598, an effort was made to strengthen the fortifications and bring them up to date. The French engineer Jean Errard'was charged with the design of the new works. He extended and remodelled the fortifications over a period of ten years.
The citadel was strengthened, which included constructing a demi-lune facing the town. The town's defences were also reinforced, retaining the double-ditch from the English period, but there were now bastions to flank the walls more effectively.
In 1604, Fort Risban was also updated and furnished with two demi-bastions'facing west, along the spit that linked it to the mainland. The tower was lowered to reduce its vulnerability to artillery fire. The fort was now well protected against an attack from land or sea.
The fortifications of Calais were again the focus of attention in the 1630s. France was again at war with Spain and the Spanish fortress at Gravelines was too close for comfort.
In the end, not much work was done, but importantly a hornwork'was added to Fort Nieulay. This hornwork protected the sluice gates, which had hitherto been outside the fort's walls. By 1640 Calais was a well-protected up-to-date fortified town.
The fortifications then remained largely unaltered until the last quarter of the 17th century. Although Louis XIV's'wars had moved the frontier northwards (Gravelines and Dunkirk were now in French hands), Calais was still an important fortress and port.
For this reason, the French engineer Vauban'visited Calais in 1675 to survey the fortifications. He perceived that the key to the town's landward defences was the sluice-bridge at Nieulay. He was concerned that the sluices were outside the main fort.
To guard against the possibility of the sluices being taken by surprise (as in 1558), Vauban proposed a complete rebuild of Fort Nieulay. His design was for a much larger fort that encompassed the sluice-bridge, straddling the canal.
The fort was rectangular, with the canal piercing the longest sides (the north and south sides). There were demi-lunes and a covered way'on the west, north and south sides, as well as a large hornwork to the west. The south side was less vulnerable because of the wet ground there.
The fort was equipped with barracks (for up to 5,000 men), stores, a chapel and a powder magazine. Work on the new Fort Nieulay began in 1677 and was mostly complete by the 1690s. The core of the fort was built first and the earthen outworks added afterwards.
Vauban was not impressed with Fort Risban, describing it as "a nice place to spend a Sunday afternoon", but of little defensive value. He proposed strengthening it by the construction of a demi-lune on its western side, but the plan was rejected due to a lack of funds.
Vauban also made minor adjustments to the town's fortifications and the citadel, improving the trace and restoring the walls where they had become decayed through neglect. On the east side of the town, the defences were reinforced by a line of lunettes'and a second covered way.
At the time of his second visit in 1689, Fort Nieulay was almost complete, so the landward defences were secure, but a new threat was emerging: the combined Anglo-Dutch naval forces. Calais was vulnerable to a naval attack and there were no coastal batteries.
It was feared that if an Allied force landed on the beach to the west of the town, they could bypass Fort Nieulay by marching along the shoreline to Fort Risban. To prevent this, two redoubts'were built in 1690.
One redoubt, called Fort Lapin, stood on the shore to the north of Fort Nieulay and the other, called Fort Crabbe, was between the citadel and Fort Nieulay. These redoubts were simple square works revetted in stone, armed with 4 guns and manned by detachments of roughly ten men, commanded by a sergeant. However, these were not coastal batteries, so they could not prevent enemy ships from coming within range of the town and the port.
Since Calais lies on a straight section of coastline, there was no easy way to fortify the maritime approaches (as opposed to many towns in Brittany, where ships must navigate into a bay full of rocks, which provided excellent locations for defensive batteries). A scheme to build a battery on piles was mooted in 1691, but was rejected on the grounds of cost.
In 1694 the English fleet set out to bombard the ports on the north coast of France. After having little success at Dunkirk due to the strong coastal fortifications, the English attacked Calais. The bomb vessels fired over a hundred shells into the town.
Bad weather forced the English fleet to withdraw before more damage was done, but the bombardment had exposed the inadaquecy of the coastal defences at Calais. In response Jean Caligny (the engineer in charge of the fortresses in Maritime Flanders) revived the 1691 plan for a pile battery.
The result was Fort Rouge, a battery consisting of a solid wooden platform supported by many wooden stilts on a base of pilings. The fort was on the low tide mark, as far out to sea as it could be built, but where the water was shallow so that large ships could not come near to attack it.
The purpose of the fort was to extend the range of the defenders' artillery out to sea, thus preventing enemy ships from coming close to the town. It was initially armed with fourteen 24-pounder and 18-pounder guns. A small wooden building held the magazine, stores and barracks.
The fort was painted red on Vauban's suggestion, since it stood on the port side of the harbour entrance. The garrison was 50 men in wartime or 10 men in peacetime, who arrived and left at low tide via a trapdoor and a ladder. There was a hoist for lifting supplies from a boat onto the platform.
Fort Rouge was put to the test in 1695 shortly after it was completed. An English fleet arrived and found the new battery preventing a bombardment from the same position as in 1694. After failing to destroy Fort Rouge using fireships and small boats, the English bombarded the town from a position east of the harbour entrance.
In 1696 the English bombarded Calais again from the east. Although these bombardments were less successful than the 1694 attack, they still posed a threat to Calais. As a result, Caligny built another pile battery, Fort Vert, to the east of the harbour entrance in 1696.
Fort Vert (the green fort) was more complex, consisting of two linked platforms on stilts. It was followed in 1701 by Fort de l'Estran (the foreshore fort), a pile battery situated between Fort Rouge and Fort Lapin.
The value of the sea forts was proved by the failure of the attack on Fort Rouge in 1695, but they required constant maintainence because they were continually damaged by storms. By the War of the Spanish Succession'the Allies had realised that the costly bombardments of the previous war had achieved little, so they resorted to blockading tactics. This reduced the importance of the sea forts, but they still played a role in protecting French shipping that was escaping from the Allies naval forces.
In 1739 Fort de l'Estran was accidentally burned (fire was a constant risk to the wooden forts) and Fort Vert was demolished in 1777 because it had fallen into disrepair. Fort Rouge however, was maintained and later used as a lighthouse to guide ships into the harbour.
In 1799 the powder magazine at Fort Risban exploded, prompting a major rebuild in the 19th century. The western demi-bastioned front was kept, but a new bastion was added in the north and a loopholed'wall on the south and east sides.
Fort Rouge saw action again in 1805, during the Napoleonic Wars. This time a British naval force was tasked with destroying the fort, which had been sheltering French ships running into Calais harbour. However, the attack failed when the fireship intended to strike the fort ran aground on the end of the western jetty and the experimental torpedoes failed to go off.
In the second half of the 19th century, the fortifications of Calais began to lose their importance. The town's defences were demolished to make way for an enlarged harbour and Fort Rouge was dismantled. However, the citadel remained occupied by the army.
In the first half of the 19th cneutry the marshes around the town were reclaimed, so they could no longer be flooded. This meant that Fort Nieulay lost its strategic value. The fort was not demolished, but it was abandoned and left to decay. Fort Risban was also not demolished, being used as a supply depot for ships in the harbour.
The surviving fortifications were all damaged in the Second World War, but substantial remains can be seen today. Of the town's defences and the sea forts, nothing remains above ground, although a canal follows the line of the ditch surrounding the town.
Calais citadel was shelled by the British navy during the Second World War, destroying the north wall and all the internal buildings. The fortifications are mostly intact and in good condition. The citadel now houses a stadium and is open to visit for free most days.
In 1940, the French garrison of Fort Nieulay heroically struggled against the nazi advance to delay the fall of Calais. The fort was heavily damaged in this action, but it has recently been restored and can be visited for free (afternoons only).
Most of the internal buildings were destroyed in the War, but the powder magazine has been restored and holds an exhibition on the history of the fort. The walls themselves are in good condition, apart from the outworks, which are only earthworks today.
Restoration work has recently been carried out at Fort Risban, and the landward part of the fortifications now appear as they did after Vauban's modifications. A sailing club uses the inside of the fort today, but there is access to all the fortifications.
On the seaward side, there are the remains of a small bunker built by the nazis. To the north of Fort Nieulay are the remains of a small square earthwork redoubt called the Gloriette Redoubt. Although it is not a spectacular fortification, it is remarkable for being a rare survivor of a once-common defence work.
The main train station, Calais Ville, lies just to the south of the citadel and the ferry port, for those arriving from the UK, is opposite Fort Risban. Fort Risban and Fort Nieulay are both within 10 minutes walk of the citadel. All three can be visited free of charge.