In the late 12th century the Duke of Brabant founded a town on a wooded patch of high ground in the marshes. The new town was called 's-Hertogenbosch (literally "Duke's Wood"), but I will follow the English convention of referring to the town by its French name, Bois-le-Duc.
From the outset, the town was conceived as a fortress to guard against invasions into Brabant from the north. In 1203 Bois-le-Duc was captured and destroyed, but it was soon rebuilt and by 1225 the first set of stone walls had been built around the town.
The population grew rapidly and by the mid-14th century a new circuit of walls had to be built to protect the enlarged town.
The first adaptations to artillery were made in 1518, when the walls and towers were reduced in height and backed with earth to strengthen them. In the 1540s the town was ordered to build large earthen platforms so that artillery could be sited on the walls.
The Italian engineer Alessandro Pasqualini'(who later designed the fortress of Jülich) was hired to make improvements to the defences. Pasqualini built a bastion'in front of the Orthenpoort gate on the north side of the town and a bulwark was built in front of the Hinthamer Poort gate.
During the Eighty Years War'the town was initially held by the Spanish. In 1587 the Dutch built a a small fortification called Fort Crèvecoeur to the north of the town on the river Meuse (Maas). This fort allowed the Dutch to cut Bois-le-Duc off from the north.
Maurice of Nassau attempted to take Bois-le-Duc in 1601 and 1603, using Fort Crèvecoeur as a base for the Dutch attacks. Both sieges failed because of the inundations'around the town that made it difficult to construct siegeworks.
In 1609 the Twelve Year Truce was declared between the States and Spain. During this period the fortifications of Bois-le-Duc were considerably strengthened by the Spanish. From 1610 the engineer Jan van der Weeghen drew up plans for improving the defences.
The Dutch had used the dry ground in the south to make their earlier attacks, so this ground needed to be protected. Fort St. Antonie, a small bastioned fort, had already been built by 1597, but van der Weeghen felt that more protection was needed.
He designed a new pentagonal fort, called Fort Isabella, was built to the south of Fort St. Antonie in 1614. The new fort had a covered way'and a flooded ditch. There was a hornwork'extending southwards, facing the most likely direction of attack.
From 1618-1620 the town walls were strengthened with the construction of nine new bastions. However, these did not form a coherent trace of mutually flanking bastions, since the walls were only vulnerable in certain places because of the marshy ground.
For instance the Bastion Vught (see right) flanked the wall on its left but was not supported by another bastion on this side. In 1623 another pentagonal fort (called Fort St. Michael) was built, this time guarding the south-eastern approach to the town.
Bois-le-Duc had become known as the Swamp Dragon because of its marshy surroundings and the failed Dutch attempts to capture it. However, the reinforced fortifications were soon put to the test. In 1629 the Dutch commander Prince Frederick Henry of Orange attacked the town with a large army.
In an epic siege the Dutch constructed lines of circumvallation around the fortress and diverted rivers to drain the marshes. The main attack was in the south-west, despite the strong fortifications there. Fort Isabella and Fort St. Antonie were taken first.
Finally the attackers made a breach in the Vught Bastion, forcing the Spanish garrison to capitulate. The fortress held out for over four months, but its fall was a great loss to the Spanish and an impressive achievement for the Dutch.
Following the capture of Bois-le-Duc, the Dutch made some improvements to the fortifications. Firstly, a new bastion was constructed on the long south curtain wall. This wall had previously been left as the medieval wall, lowered and backed with earth.
However during the 1629 siege the Bastion Vught had suffered from a lack of supporting fire from this part of the defences. The new bastion, called the Bastion Oranje, was able to support the Bastion Vught and to flank the wall to the east.
The Bastion Oranje itself was not flanked by adjacent bastions, as it would be in a regular fortification, but it was unlikely to be attacked due to the marshy ground in front of it. Its main role was to support the Bastion Vught and the south end of the fortress.
The Dutch also built a citadel'from 1635-1640. They were concerned that the population of Bois-le-Duc was predominantly Catholic and potentially pro-Spanish, so the citadel was partly built to guard against a revolt.
Initially the citadel was to be built in the centre of the town, where it would be most imposing. However Frederick Henry, who had promised the inhabitants religious freedom, used his influence to have it constructed in the north, where it could form part of the fortifications.
The citadel was called Fort Willem Maria after Frederick Henry's two children. It was known as Papenbril (meaning "Pope Glasses") by the townspeople, because it was built to watch over the Catholic population.
The citadel is pentagonal with five bastions. It was built on the site of the Bastion Orthenpoort, which was demolished to make way for it. Two of its bastions were on the inside (facing the town) and the other three were external, forming part of the town's defences.
Nearby houses were demolished in order to form an esplanade, an unobstructed patch of ground so that the citadel had a clear field of fire towards the town.
The outer forts were maintained and manned by the new Dutch garrison, including a new fort called Fort Orthen. Fort Orthen was built in 1630, shortly after the Dutch capture, to protect the northern approaches to the town. It was an earthwork fort with four bastions.
Bois-le-Duc remained in Dutch hands for the rest of the war and became one of the strong border fortresses of the Republic, defending the frontier with the Spanish Netherlands to the south. Although it was not attacked again, it was maintained and strengthened over the years.
In 1672 the Pettelaarse Schans was abandoned and slighted, because it was decided that it was not worth garrisoning, and the Dutch did not want it to fall into the hands of the French. The fortifications of Bois-le-Duc were restored and improved by Menno van Coehoorn'in the 1690s.
He had a covered way and demi-lunes'built to reinforce vulnerable sections of the fortifications. More reinforcements were carried out in the 18th century, when Fort Orthen was rebuilt and a powder magazine'was built in the citadel.
In 1794 the French captured Bois-le-Duc after a short bombardment. In 1810 it was made the capital of the Lower Rhine region, but in 1813 the Prussians drove the French out of the Netherlands. Bois-le-Duc became part of the Kingdom of the Netherlands.
In the 1830s, following the Belgian Revolution, a number of outlying redoubts called the Vught Lunettes were built to defend the fortress against an attack from the south. In 1874 the fortifications of Bois-le-Duc were declassified, but since they formed the edges of the waterways there was little demolition. In 1880 the south bastion of the citadel was removed so that large barges could enter the town.
Much of the enceinte around the town has survived to this day. The fortifications are been restored so that visitors can walk round the walls. The Bastion St. Antonie (left) has been partially restored with ramparts and some artillery, to show how it would have looked.
An exhibition called Bastionder to house archeological finds relating to the fortifications has been created in the Bastion Oranje. The Bastion Deuteren and most of the Bastion Vught have been demolished, but part of Fort St. Antonie and the outer traces of Fort Isabella have survived.
A house has been built on the south bastion of Fort St. Antonie, but it is still possible to appreciate the original form of the small fort, especially as the bastion on the east side (see right) has been cleared and restored. The gatehouse of Fort Isabella can also be seen.
The western walls are currently undergoing restoration (2009), including the Maria Bastion, which was almost finished when I visited.
This bastion sticks out into the river, so it will probably not be fully restored so that the river traffic is not inhibited. The northern section of the west wall is used as a harbour for pleasure boats, which is very busy in the summer.
The citadel has also survived and is in good condition, apart from the south bastion, which was demolished to make way for shipping. It is no longer surrounded by water, but the ditch on the north side still exists, so it is easy to imagine what the citadel as a whole would have looked like in the 17th century.
The original gatehouse on the south side has been removed and there is no bridge to the gate on the north side. The earth ramparts and artillery ramps on the inside have been restored and the surviving internal buildings date from the 18th and 19th centuries.
An interesting 17th century powder magazine built by the Spanish stands near the citadel. It is hexagonal and was designed so that an accidental explosion would do as little damage as possible to the town. The magazine can be visited on a guided tour.
The rough outlines of Fort St. Michael (the Pettelaarse Schans) and part Fort Orthen can be made out, but nothing substantial remains of these forts. The fortress of Bois-le-Duc is unique because of its location and the techniques that were employed to defend it.
Instead of consisting of a systematic bastioned trace, the fortificatons were designed to protect the only places where an attacker could make trenches and batteries.
Bois-le-Duc is an interesting fortress to visit with plenty of visible remains. It is easy to understand the nature of the defences by walking around them, although much of the surrounding land has now been drained and built on.
Bois-le-Duc ('s-Hertogenbosch) is easy to reach by car from nearby cities (four motorways meet at the city) and there is a mainline station on the west side of the town centre.