siege

A siege is a military operation in which an attacking force surrounds a fortified place, aiming to compel surrender by cutting off supplies, reinforcements, and communications, while applying sustained pressure. The objective is to breach defenses, force capitulation, or starve the garrison into submission. Sieges can last from days to years and often involve combined land, river, or sea components and efforts to block entry to the besieged location.

Historically, siege methods evolved with technology. In antiquity and the Middle Ages, attackers used trenches, ramps, mining, and siege engines such as battering rams and towers to breach walls, while defenders reinforced fortifications and conducted countermines or breakout attempts. The rise of gunpowder transformed fortifications and tactics, leading to the development of star forts and large gun batteries designed to withstand bombardment. Notable sieges include Alesia (Caesar’s siege of Vercingetorix, 52 BCE); Jerusalem (70 CE); Orléans (1429); and Constantinople (1453). In the 20th century, sustained encirclements such as Leningrad (1941–1944) and Stalingrad (1942–1943) illustrate how sieges persisted in modern warfare.

Techniques commonly employed in sieges include establishing a siege line or circumvallation to encircle the target, constructing siege works, mining and sapping to breach walls, and bombarding defenses with artillery. Blockades restrict supplies, and relief forces may attempt to break the siege or negotiate capitulation. Defenders may attempt sally operations or use guerrilla tactics within the besieged area.

Today, siege operations are governed by international law, and deliberate starvation of civilians is prohibited. In modern conflict, sieges are less common due to airpower and rapid offensives, but encirclements and blockades continue to occur in various theaters.