Sebastian Le Prestre de Vauban was the one of the seventeenth century’s foremost military specialists, an expert on building and conquering fortifications.
A Brief And Incomplete History of European Fortification
Everyone is familiar with that symbol of the Middle Ages, the fortified castle. It seems truly impregnable--and by the armies of the time, it was, or at least only able to be overcome by a costly siege. The main principles of its construction were simple: thicker and taller is better. This seems obvious: after all, the higher a wall or fence is, the harder it is to get over it, and the thicker it is, the harder it is to get through it.
The development of gunpowder, and, more specifically, mortars and artillery changed this equation drastically. The higher a wall was, the better was the target it provided for cannon--as was nicely demonstrated during the 1453 fall of Constantinople, where the massive Ottoman siege train pounded large parts of that city’s huge and ancient walls into rubble. Clearly, a new approach to fortification was needed.
This was provided in the XVI century by the bastion, a low, bunker-like structure that provided both protection from cannon and enemy soldiers. It consisted of a ditch and a parapet behind it--both sloped as to prevent direct mortar and cannon fire. In front of the ditch, there was a sloped glacis, which served to prevent horizontal fire at the parapet. There was also a covered way, to allow defending soldiers to fire without danger from enemy artilllery. The bastion protruded from the wall, in order to maximize the field of fire of the defendants and to present the smallest area to the fire of the enemy. As a result of this, XVI-XVIII-century forts look like stars, surrounded by bastions on all sides.
As a result of this development, sieges became very difficult to pursue successfully, and unless the defendants were undermanned or undersupplied they were usually victorious. For example, the order of the Knights Hospitalliers defended their fortress on Malta from a large Ottoman army with relative ease and only had to negotiate a (very reasonable) surrender when they ran out of ammunition.
The French Marshal Vauban was a relatively rare specimen in the army of Louis XIV. He was born a commoner, and had worked his way up through the ranks because of his skill at fortification. He designed a number of French fortresses and had written several pamphlets.
It was at the siege of the Dutch city of Maastricht in 1673 that he invented siege by parallels, which was to change the siege business of the time for good.
Essentially, his approach consisted of this:
Dig trenches in a ring or arc around the bastion, then build zigzagging passages towards the fortress, and dig another trench, forming concentric rings (or parallel arcs), and continue this as necessary. Protected by the trenches, the besieging army could make its way right up to the walls and then inside the fortress.
After this approach (no pun intended) was tried, no one even used anything else anymore. The siege of Cambrai in 1676 was done in broad daylight, with great success.
Later, Vauban developed some enhancements--such as the use of mines, an ancient tactic, and the use of ricochet fire. However, the principle remained the same, and he conducted a large number of other sieges, successfully. He also designed and built French fortresses, keeping his own tactics in mind. However, fortification’s importance was greatly reduced following his innovations; walls would never again be trusted as they once were. Needless to say, his theories influenced the trench warfare of the nineteenth and twentieth centuries also.
He died March 30, 1707--a hundred years later, his heart was placed by Napoleon in the church of Les Invalides in Paris.