Editing Siege (section)

==Age of gunpowder==
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The introduction of gunpowder and the use of [[cannon]]s brought about a new age in siege warfare. Cannons were first used in [[Song dynasty]] China during the early 13th century, but did not become significant weapons for another 150 years or so. In early decades, cannons could do little against strong castles and fortresses, providing little more than smoke and fire. By the 16th century, however, they were an essential and regularized part of any campaigning army, or castle's defences.

The greatest advantage of cannons over other siege weapons was the ability to fire a heavier projectile, farther, faster, and more often than previous weapons. They could also fire projectiles in a straight line, so that they could destroy the bases of high walls. Thus, 'old fashioned' walls – that is, high and, relatively, thin – were excellent targets, and, over time, easily demolished. In 1453, the [[Walls of Constantinople|Theodosian Walls]] of [[Constantinople]], the capital of the [[Byzantine Empire|Roman Empire]], were broken through in [[Fall of Constantinople|just six weeks]] by the 62 cannons of [[Mehmed the Conqueror|Mehmed II]]'s army, although in the end the conquest was a long and extremely difficult siege with heavy Ottoman casualties due to the repeated attempts at taking the city by assault.

[[File:Sixteenth Century Cannon2.jpg|thumb|right|upright|Late 16th-century illustration of [[cannon]] with [[gabion]]s]]

However, new fortifications, designed to withstand gunpowder weapons, were soon constructed throughout Europe. During the [[Renaissance]] and the [[early modern period]], siege warfare continued to dominate the conduct of the European wars.

Once siege guns were developed, the techniques for assaulting a town or fortress became well known and ritualized. The attacking army would surround a town. Then the town would be asked to surrender. If they did not comply, the besieging army would surround the town with temporary fortifications to stop [[Sally (military)|sallies]] from the stronghold or relief getting in. The attackers would next build a length of trenches parallel to the defenses (these are known as the "first parallel") and just out of range of the defending artillery. They would dig a trench (known as a forward) towards the town in a [[zigzag]] pattern so that it could not be [[enfilade]]d by defending fire. Once they were within artillery range, they would dig another parallel (the "second parallel") trench and fortify it with gun emplacements. This technique is commonly called entrenchment.

If necessary, using the first artillery fire for cover, the forces conducting the siege would repeat the process until they placed their guns close enough to be laid (aimed) accurately to make a breach in the fortifications. In order to allow the [[forlorn hope]] and support troops to get close enough to exploit the breach, more zigzag trenches could be dug even closer to the walls, with more parallel trenches to protect and conceal the attacking troops. After each step in the process, the besiegers would ask the besieged to surrender. If the forlorn hope stormed the breach successfully, the defenders could expect no mercy.

===Emerging theories===
The castles that in earlier years had been formidable obstacles were easily breached by the new weapons. For example, in Spain, the newly equipped army of [[Ferdinand and Isabella]] was able to conquer [[Moors|Moorish]] strongholds in [[Granada]] in 1482–1492 that had held out for centuries before the invention of cannons.

In the early 15th century, Italian architect [[Leon Battista Alberti]] wrote a treatise entitled ''De Re aedificatoria'', which theorized methods of building fortifications capable of withstanding the new guns. He proposed that walls be "built in uneven lines, like the teeth of a saw". He proposed star-shaped fortresses with low, thick walls.

However, few rulers paid any attention to his theories. A few towns in Italy began building in the new style late in the 1480s, but it was only with the French invasion of the Italian peninsula in 1494–1495 that the new fortifications were built on a large scale. [[Charles VIII of France|Charles VIII]] invaded Italy with an army of 18,000 men and a horse-drawn [[siege-train]]. As a result, he could defeat virtually any city or state, no matter how well defended. In a panic, military strategy was completely rethought throughout the Italian states of the time, with a strong emphasis on the new fortifications that could withstand a modern siege.

===New fortresses===
[[File:Atlas Van der Hagen-KW1049B12 098 1-Stadsprofiel van- CANDIA.jpeg|thumb|upright=1.3|The [[siege of Candia]], regarded as one of the longest sieges in history (1648–1669)]]

The most effective way to protect walls against cannon fire proved to be depth (increasing the width of the defenses) and angles (ensuring that attackers could only fire on walls at an oblique angle, not square on). Initially, walls were lowered and backed, in front and behind, with earth. Towers were reformed into triangular bastions.{{sfn|Townshend|2000|p=211}} This design matured into the ''[[trace italienne]]''. [[Star fort|Star-shaped fortresses]] surrounding towns and even cities with outlying defenses proved very difficult to capture, even for a well-equipped army.{{sfn|Townshend|2000|p=212}} Fortresses built in this style throughout the 16th century did not become fully obsolete until the 19th century, and were still in use throughout World War I (though modified for 20th-century warfare). During World War II, ''trace italienne'' fortresses could still present a formidable challenge, for example, in the last days of World War II, during the [[Battle in Berlin]], that saw some of the heaviest urban fighting of the war, the Soviets did not attempt to storm the [[Spandau Citadel]] (built between 1559 and 1594), but chose to [[investment (military)|invest]] it and negotiate its surrender.{{sfn|Beevor|2002|pp=372–375}}

However, the cost of building such vast modern fortifications was incredibly high, and was often too much for individual cities to undertake. Many were bankrupted in the process of building them; others, such as [[Siena]], spent so much money on fortifications that they were unable to maintain their armies properly, and so lost their wars anyway. Nonetheless, innumerable large and impressive fortresses were built throughout northern Italy in the first decades of the 16th century to resist repeated French invasions that became known as the [[Italian Wars]]. Many stand to this day.
[[File:Sitio de Ostende.jpg|thumb|The [[Siege of Ostend]] during the [[Eighty Years' War]], 1601–1604]]
In the 1530s and 1540s, the new style of fortification began to spread out of Italy into the rest of Europe, particularly to France, the Netherlands, and Spain. Italian engineers were in enormous demand throughout Europe, especially in war-torn areas such as the Netherlands, which became dotted by towns encircled in modern fortifications. The densely populated areas of [[Northern Italy]] and the [[Dutch Republic|United Provinces]] (the Netherlands) were infamous for their high degree of fortification of cities. It made campaigns in these areas very hard to successfully conduct, considering even minor cities had to be captured by siege within the span of the campaigning season. In the Dutch case, the possibility of flooding large parts of the land provided an additional obstacle to besiegers, for example at the [[siege of Leiden]]. For many years, defensive and offensive tactics were well balanced, leading to protracted and costly wars such as Europe had never known, involving more and more planning and government involvement. The new fortresses ensured that war rarely extended beyond a series of sieges. Because the new fortresses could easily hold 10,000 men, an attacking army could not ignore a powerfully fortified position without serious risk of counterattack. As a result, virtually all towns had to be taken, and that was usually a long, drawn-out affair, potentially lasting from several months to years, while the members of the town were starved to death. Most battles in this period were between besieging armies and relief columns sent to rescue the besieged.

===Marshal Vauban and Van Coehoorn===
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[[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.

===Siege warfare===
Siege warfare dominated in Western Europe for most of the 17th and 18th centuries. An entire campaign, or longer, could be used in a single siege (for example, [[Siege of Ostend|Ostend]] in 1601–1604; [[Siege of La Rochelle|La Rochelle]] in 1627–1628). This resulted in extremely prolonged conflicts. The balance was that, while siege warfare was extremely expensive and very slow, it was very successful—or, at least, more so than encounters in the field. Battles arose through clashes between besiegers and relieving armies, but the principle was a slow, grinding victory by the greater economic power. The relatively rare attempts at forcing [[pitched battle]]s ([[Gustavus Adolphus]] in 1630; the French against the Dutch in 1672 or 1688) were almost always expensive failures.

[[File:Bataille Yorktown.jpg|thumb|left|Storming of redoubt #10 during the [[siege of Yorktown]]]]

The exception to this rule were the English.{{sfn|Baldock|1809|pp=515–520}} During the [[English Civil War]], anything which tended to prolong the struggle, or seemed like want of energy and avoidance of a decision, was bitterly resented by the men of both sides. In France and Germany, the prolongation of a war meant continued employment for the soldiers, but in England, both sides were looking to end the war quickly. Even when in the end the [[New Model Army]]—a regular professional army—developed the original decision-compelling spirit permeated the whole organisation, as was seen when pitched against regular professional continental troops the [[Battle of the Dunes (1658)|Battle of the Dunes]] during the [[Interregnum (England)|Interregnum]].<ref>{{EB1911|inline=1 |first=Charles Francis |last=Atkinson|wstitle=Great Rebellion#The_Royalist and Parliamentarian Armies |display=Great Rebellion: 2. The Royalist and Parliamentarian Armies| volume=12 |page=403}}</ref>

[[File:Battle of Badajoz.jpg|thumb|British infantry attempt to scale the walls of [[Siege of Badajoz (1812)|Badajoz]], Peninsular War, 1812]]

Experienced commanders on both sides in the English Civil War recommended the abandonment of garrisoned fortifications for two primary reasons. The first, as for example proposed by the Royalist [[Sir Richard Willis, 1st Baronet|Sir Richard Willis]] to King Charles, was that by abandoning the garrisoning of all but the most strategic locations in one's own territory, far more troops would be available for the field armies, and it was the field armies which would decide the conflict. The other argument was that by slighting potential strong points in one's own territory, an enemy expeditionary force, or local enemy rising, would find it more difficult to consolidate territorial gains against an inevitable counterattack. Sir [[John Meldrum]] put forward just such an argument to the Parliamentary [[Committee of Both Kingdoms]], to justify his slighting of [[Gainsborough, Lincolnshire|Gainsborough]] in Lincolnshire.{{sfn|Symonds|1859|p=270}}{{sfn|Firth|1902|p=29}}

Sixty years later, during the [[War of the Spanish Succession]], the [[John Churchill, 1st Duke of Marlborough|Duke of Marlborough]] preferred to engage the enemy in pitched battles, rather than engage in siege warfare, although he was very proficient in both types of warfare.

On 15 April 1746, the day before the [[Battle of Culloden]], at [[Dunrobin Castle]], a party of [[William Sutherland, 17th Earl of Sutherland|William Sutherland]]'s militia conducted the last siege fought on the mainland of Great Britain against Jacobite members of [[Clan MacLeod]].

====Strategic concepts====
In the [[French Revolutionary Wars|French Revolutionary]] and [[Napoleonic Wars]], new techniques stressed the division of armies into all-arms corps that would march separately and only come together on the battlefield. The less-concentrated army could now live off the country and move more rapidly over a larger number of roads.

Fortresses commanding lines of communication could be bypassed and would no longer stop an invasion. Since armies could not live off the land indefinitely, [[Napoleon Bonaparte]] always sought a quick end to any conflict by pitched battle. This military revolution was described and codified by [[Carl von Clausewitz|Clausewitz]].

====Industrial advances====
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[[File:Detaille - Engineer Corps, Siege of Anvers, 1832.jpg|thumb|right|French Engineer Corps during the [[Siege of Antwerp (1832)|siege of Antwerp]], 1832]]

Advances in artillery made previously impregnable defenses useless. For example, the walls of [[Battle of Vienna|Vienna]] that had held off the [[Ottoman Empire|Turks]] in the mid-17th century were no obstacle to [[Napoleon]] in the early 19th.

Where sieges occurred (such as the [[siege of Delhi]] and the [[siege of Cawnpore]] during the [[Indian Rebellion of 1857]]), the attackers were usually able to defeat the defenses within a matter of days or weeks, rather than weeks or months as previously. The great Swedish white-elephant fortress of [[Karlsborg Fortress|Karlsborg]] was built in the tradition of Vauban and intended as a reserve capital for Sweden, but it was obsolete before it was completed in 1869.

Railways, when they were introduced, made possible the movement and supply of larger armies than those that fought in the Napoleonic Wars. It also reintroduced siege warfare, as armies seeking to use railway lines in enemy territory were forced to capture fortresses which blocked these lines.

During the [[Franco-Prussian War]], the battlefield front lines moved rapidly through France. However, the Prussian and other German armies were delayed for months at the [[Siege of Metz (1870)|siege of Metz]] and the [[Siege of Paris (1870–1871)|siege of Paris]], due to the greatly increased firepower of the defending infantry, and the principle of detached or semi-detached forts with heavy-caliber [[artillery]]. This resulted in the later construction of fortress works across Europe, such as the massive fortifications at [[Verdun-sur-Meuse|Verdun]]. It also led to the introduction of tactics which sought to induce surrender by bombarding the civilian population within a fortress, rather than the defending works themselves.

The [[Siege of Sevastopol (1854–1855)|siege of Sevastopol]] during the [[Crimean War]] and the [[siege of Petersburg]] (1864–1865) during the [[American Civil War]] showed that modern citadels, when improved by improvised defences, could still resist an enemy for many months. The [[siege of Plevna]] during the [[Russo-Turkish War (1877–1878)]] proved that hastily constructed field defenses could resist attacks prepared without proper resources, and were a portent of the trench warfare of World War I.

Advances in firearms technology without the necessary advances in battlefield communications gradually led to the defense again gaining the ascendancy. An example of siege during this time, prolonged during 337 days due to the isolation of the surrounded troops, was the [[siege of Baler]], in which a reduced group of Spanish soldiers was besieged in a small church by the [[Philippines|Philippine]] rebels in the course of the [[Philippine Revolution]] and the [[Spanish–American War]], until months after the [[Treaty of Paris (1898)|Treaty of Paris]], the end of the conflict.

Furthermore, the development of [[steamship]]s availed greater speed to [[blockade runner]]s, ships with the purpose of bringing cargo, e.g. food, to cities under blockade, as with [[Charleston, South Carolina]], during the American Civil War.