Throughout history, the desire to capture a fortified position in order to acquire territory has generally taken precedence over battles, raids, and other military adventures, especially in ancient, medieval, and early modern times. Because of this, specific tactics and technology were continually being devised and refined in order to diminish the time it took to wage a successful siege. The attack and defence of fortresses did not simply demand the techniques of fortification and siegecraft, but shaped a form of warfare in which the siege played a central role.
Before gunpowder weaponry altered the time required to conduct a siege, there were four means of successfully capturing a fortified site. The first, and least violent, was the negotiated capitulation, to take place should a relief army not appear by a certain date. Negotiation occurred when the besieger either did not necessarily wish to capture the besieged site, but wished instead to use the siege as leverage to force a battle against the army of the site's owner, or when the besieger knew that no relief army would be able to come to the aid of the besiegers and wished to lessen his own losses and minimize damage to the fortress. An example of the former occurred in 1314 when Robert Bruce used the siege of Stirling castle to provoke the battle of Bannockburn against Edward II; examples of the latter were seen in the sieges of numerous Norman castles by Henry V in 1417-20, most of which submitted to him when no French relief army appeared before the day negotiated for their capitulation.
A second means of forcing the surrender of a fortification was through starvation by blockade. Eventually, should those delivering supplies not be able to evade the blockade, hunger would force those besieged to surrender. While the most frequent means of capturing a fortification, starvation often required a lengthy siege, sometimes lasting longer than a year, such as at Calais in 1346-7. The process could easily misfire, for the besieged might well have stocks of provisions which the besiegers lacked: sometimes it was the latter who starved. A military commander (the governor) might expel ‘useless mouths’ from his fortress in order to conserve supplies, but a harsh besieger might refuse to let them depart.
A third means of capturing a fortification was the bribery of one of the besieged to open a gate or otherwise to assist the entry into the fortification by the besiegers. This generally became an option only when the inhabitants had some reason for accepting the bribe, a relationship with the besiegers, or when suffering from starvation, they became desperate to end a siege. Bribery is credited with the surrender of Rome in 410, Antioch in 1098, and Château Gaillard in 1204.
The most costly, in terms of casualties among the besiegers, but perhaps the most quick means of capturing a besieged site, was the assault. Should a besieger not wish to spend the time required to force submission by starvation, to find an opportunity for bribery, or to negotiate a capitulation, an option was to attempt to take the besieged place by force. This could be achieved by going under, through, or over the walls or gates of a fortress. Going under required mines. A tunnel, supported by wood, would be dug beneath the walls, and then the wooden supports would be burnt, causing the wall above to collapse. Successfully countering this generally required a counter-mine. Mining is generally credited with the fall of Jericho to the Israelites in c.1350 bc. Going through the walls or gates of a fortified site generally required a means of breaching those fortifications (see siege engines) to create a breach in a wall or gate through which attacking besiegers might gain access to the fortified site. To prevent such an assault, defenders were forced to attack the siege engines or their operators to prevent a breach in their fortifications. Constantinople was captured in 1453 after Ottoman Turks breached that city's strong walls.
Finally, going over the walls of a besieged fortress generally required scaling ladders or a siege tower. By using these devices, besiegers would climb over the walls and gain access to the site and its inhabitants. This was a particularly risky means of concluding a siege as the attackers using ladders would be continually assailed from above on their climb up the walls. A covered siege tower did provide some protection for the attackers, but even with this protection did not often prevent the first attackers from meeting stiff opposition to their assault. Still, going over the walls by means of siege towers is credited with causing the fall of Jerusalem in 1099.
The advent of gunpowder weapons signalled great changes. By the end of the 14th century, cannon were able to demolish the high walls which had previously resisted attack. In an effort to counter the new weapons, gunports and artillery towers were added to old fortifications, while new ones were built in the lower, more angular style of the trace italienne. With the advent of artillery fortification, sieges once again became long-drawn-out affairs, although the development of associated techniques of siegecraft meant that an attacker who knew his business and was not dislodged by a relieving army, would generally be able to proceed methodically towards the reduction of a fortress.
The advent of artillery fortification, with the bastion as its defining feature, saw the development of techniques which saw the besieger establish himself outside the fortress and then proceed methodically, through systems of parallel trenches linked by zigzag saps, to breach the ramparts by mining or the fire of heavy guns and either deliver an assault or accept capitulation. The siege was a major feature of campaigns in 18th-century Europe, and many of the battles of the era were focused on the desire of the adversaries to maintain or raise a siege. Thus in 1709 Marlborough was besieging Mons when a French army threatened him from the south: he went out and beat it, though at terrible cost, at Malplaquet. In 1745 Saxe was battering Tournai when Cumberland marched to its relief, only to be beaten at Fontenoy.
As artillery fortification spread, unsurprisingly, to the overseas possessions of European powers, so too did siege warfare. For example, in 1761 Eyre Coote took Pondicherry, noting that the defences were in no fit state to stand a formal siege, while the Spanish fortress of Havana on the island of Cuba was taken by the British in the following year after a sharply contested siege which ended with capitulation and the honours of war. In North America, Montcalm took Fort Oswego by siege in 1756 (the unlucky governor was decapitated by a roundshot), and proved, as Christopher Duffy has written, that ‘meticulously-planned advances and formal siege attacks were as effective in backwoods warfare as in the plains of Flanders’.
By the time of the French Revolutionary wars, sieges had ceased to be the central business of warfare and the style of warfare which featured them had begun to change. Duffy suggests that it was not simply the improved power of attack that was responsible, but that the bigger armies of the late 18th century, subject to increasingly effective central authority, made it easier for an invader to flow between fortresses, masking them if he chose to, to push his attack deep into the heart of the enemy's country. Nevertheless, if sieges had lost much of their former importance, and no longer shaped the wars of the 19th century as they had those of previous centuries, they remained a part of warfare. During the Peninsular war Wellington besieged and stormed Badajoz and Ciudad Rodrigo, and Spanish defence of Saragossa in 1808-9 was a mark of popular resistance to the French; Paris, surrounded by a bastioned wall built in the 1840s, was besieged during the Franco-Prussian war; the siege of Port Arthur played a central part in the Russo-Japanese war; Leningrad was besieged, at extraordinary cost, in WW II, and from 1992 to 1995 Sarajevo was besieged. Sieges have often demanded as much from the beleaguered population as from their defenders, and in recent sieges popular determination, rather than the siting of breaching batteries or the defence of bastions, has been the deciding factor.
Bibliography
- Aeneas Tacticus, How to Survive under Siege, ed. and trans. David Whitehead (Oxford, 1990).
- Bradbury, Jim, The Medieval Siege (Woodbridge, 1992).
- Duffy, Christopher, Siege Warfare: The Fortress in the Early Modern World, 1494-1660 (London, 1979).
- —— The Fortress in the Age of Vauban and Frederick the Great (London, 1985).
- Kern, Paul Bentley, Ancient Siege Warfare (Bloomington, Ind., 1999)
— Kelly DeVries/Richard Holmes
