Editing Siege (section)

===Marshal Vauban and Van Coehoorn===
{{Unreferenced section|date=September 2022}}
[[File:Neuf-Brisach 007 850.jpg|thumb|left|[[Vauban]]'s star-shaped fortified city of [[Neuf-Brisach]]]]

At the end of the 17th century, two influential military engineers, the French [[Marshal]] [[Sébastien Le Prestre de Vauban|Vauban]] and the Dutch military engineer [[Menno van Coehoorn]], developed modern fortification to its pinnacle, refining siege warfare without fundamentally altering it: ditches would be dug; walls would be protected by [[glacis]]; and [[bastion]]s would [[enfilade]] an attacker. Both engineers developed their ideas independently, but came to similar general rules regarding defensive construction and offensive action against fortifications. Both were skilled in conducting sieges and defenses themselves. Before Vauban and Van Coehoorn, sieges had been somewhat slapdash operations. Vauban and Van Coehoorn refined besieging to a science with a methodical process that, if uninterrupted, would break even the strongest fortifications. Examples of their styles of fortifications are [[Arras]] (Vauban) and the no-longer-existent fortress of [[Bergen op Zoom]] (Van Coehoorn). The main differences between the two lay in the difference in terrain on which Vauban and Van Coehoorn constructed their defenses: Vauban in the sometimes more hilly and mountainous terrain of France, Van Coehoorn in the flat and floodable lowlands of the Netherlands.

Planning and maintaining a siege is just as difficult as fending one off. A besieging army must be prepared to repel both [[sortie (siege warfare)|sortie]]s from the besieged area and also any attack that may try to relieve the defenders. It was thus usual to construct lines of trenches and defenses facing in both directions. The outermost lines, known as the lines of [[contravallation]], would surround the entire besieging army and protect it from attackers.
[[File:Siege of Philipsburg 1676.jpg|thumb|The [[Siege of Philippsburg (1676)|Siege of Philippsburg]] during the [[Franco-Dutch War]], 1676]]
This would be the first construction effort of a besieging army, built soon after a fortress or city had been invested. A line of circumvallation would also be constructed, facing in towards the besieged area, to protect against sorties by the defenders and to prevent the besieged from escaping. The next line, which Vauban usually placed at about {{convert|600|m|ft}} from the target, would contain the main batteries of heavy cannons so that they could hit the target without being vulnerable themselves. Once this line was established, work crews would move forward, creating another line at {{convert|250|m|ft|-3}}. This line contained smaller guns. The final line would be constructed only {{convert|30|to|60|m|ft|sigfig=1}} from the fortress. This line would contain the [[Mortar (weapon)|mortars]] and would act as a [[staging area]] for attack parties once the walls were breached. Van Coehoorn developed a small and easily movable mortar named the [[coehorn]], variations of which were used in sieges until the 19th century. It would also be from this line that miners working to undermine the fortress would operate.

The trenches connecting the various lines of the besiegers could not be built perpendicular to the walls of the fortress, as the defenders would have a clear line of fire along the whole trench. Thus, these lines (known as [[Sapping|saps]]) needed to be sharply jagged.

[[File:Vienna Battle 1683.jpg|thumb|The [[Battle of Vienna]] took place in 1683 after [[Vienna]] had been besieged by the [[Ottoman Empire]] for two months.]]

Another element of a fortress was the [[citadel]]. Usually, a citadel was a "mini fortress" within the larger fortress, sometimes designed as a [[reduit]], but more often as a means of protecting the garrison from potential revolt in the city. The citadel was used in wartime and peacetime to keep the residents of the city in line.

As in ages past, most sieges were decided with very little fighting between the opposing armies. An attacker's army was poorly served, incurring the high casualties that a direct assault on a fortress would entail. Usually, they would wait until supplies inside the fortifications were exhausted or disease had weakened the defenders to the point that they were willing to surrender. At the same time, diseases, especially [[typhus]], were a constant danger to the encamped armies outside the fortress, and often forced a premature retreat. Sieges were often won by the army that lasted the longest.

An important element of [[strategy]] for the besieging army was whether or not to allow the encamped city to surrender. Usually, it was preferable to graciously allow a [[Surrender (military)|surrender]], both to save on casualties, and to set an example for future defending cities. A city that was allowed to surrender with minimal loss of life was much better off than a city that held out for a long time and was brutally butchered at the end. Moreover, if an attacking army had a reputation of killing and pillaging regardless of a surrender, then other cities' defensive efforts would be redoubled. Usually, a city would surrender (with no honour lost) when its inner lines of defense were reached by the attacker. In case of refusal, however, the inner lines would have to be stormed by the attacker and the attacking troops would be seen to be justified in sacking the city.