siege, assault against a city or fortress with the purpose of capturing it. The history of siegecraft parallels the development of fortification and, later, artillery. In early times battering rams and bores were employed to break down the walls and gates of a fortified place (see castle) if deception, treachery, starvation, or storm could not carry it. To protect the attackers from missiles, hot oil, and incendiaries launched by the defenders, a shelter was constructed, usually from huge wicker shields covered with wood or hide (mantelets). Mounds and movable wooden towers were built by both besieger and besieged in a race to attain heights from which the adversary could be assailed. Engines of war, such as the catapult, were brought into play by both sides to hurl stones, spears, pots of fire, and arrows. It was also common for besiegers to build a wall (circumvallation) around their objective to prevent sorties and a second wall (contravallation) around their own army as security against relieving forces. Mining was employed by the assailants from earliest times, and the besieged dug countermines in defense; such tactics greatly increased in effectiveness with the introduction of gunpowder. Artillery that could breach high walls made it necessary to lower and extend medieval fortifications and mount defensive artillery. Many sieges became artillery duels. The development of tanks, aircraft, and missiles in the 20th cent. has given the besieger a great advantage in firepower and mobility. Some notable sieges of history include those of Syracuse (415–413 BC), Jerusalem (AD 70), Acre (1189–90), Constantinople (1453), Quebec (1759–60), Sevastopol (1854–55, 1941–42), Vicksburg (1863), Port Arthur (1904), Malta (1940–43), Leningrad (1941–43), Dienbienphu (1954) and Khe Sanh (1968).
See C. W. C. Oman, Art of War in the Middle Ages (2d ed. 1924, repr. 1959); S. Toy, A History of Fortification from 3000 BC to AD 1700 (2d ed. 1966); V. Melegari, The Great Military Sieges (1972); I. V. Hogg, Fortress (1975); C. Duffy, Siege Warfare (2 vol., 1979–85).