Circumvallatie

Circumvallatie, or circumvallation, is a term used in siege warfare to describe a continuous line of fortifications erected by attackers around a besieged fortress or town. The purpose is to surround the defended place, prevent relief forces from reaching it, and isolate it by blocking supplies and reinforcements while siege operations are conducted.

Construction typically involves earthworks such as ramparts and ditches, with wooden palisades, earthen berms, batteries for artillery, and associated trenches and redoubts. The line may be complemented by a parallel outer line, the contravallation, designed to oppose external relief armies and to protect the besieging camp from attack by foes approaching from outside the circle.

Distinction: The circumvallation is the inner ring around the besieged place, while the contravallation is an outer line facing outward to resist relief efforts. Together, these lines formed a siege system intended to secure the besiegers' position.

Historical usage: Circumvallations were widely employed in the Early Modern period, especially in the Low Countries during the Dutch Revolt. Notable examples include the circumvallation around Antwerp during the siege of 1585–1586. In many sieges, the attackers built both circumvallation and contravallation as part of a methodical siege operation.

Etymology and modern note: The term derives from Latin circumvallatio, from circum- "around" and vallum "rampart". In modern military history the concept remains discussed as a foundational siege technique, though explicit circumvallations are no longer constructed in contemporary warfare.