Development Concentric castle

star-shaped plan of citadel of lille (france), designed vauban

surrounding fortresses or towns series of defensive walls outer walls lower inner walls has been found in fortifications going thousands of years cultures assyrians, persians, ancient egyptians , babylonians. ancient city of lachish, place in israel, excavated , found consist of multiple walls famously illustrated in assyrian art documenting successful siege of city. byzantines famously constructed walls of constantinople featured double layers of walls through of perimeter , moat. city of ancient babylon featured multiple layers of fortifications, famously seen in ishtar gate. however, relationship of concentric castle other forms of fortification complex. perhaps earliest example of concentric castle crusader castle of belvoir, regular rectangular layout has been described nicolle 1 castrum nested inside another. historians (in particular hugh kennedy) have argued concentric defence arose response advances in siege technology in crusader states 12th 13th century. outer wall protected inner 1 siege engines, while inner wall , projecting towers provided flanking fire crossbows. in addition, strong towers may have served platforms trebuchets shooting @ besiegers. walls typically include towers, arrow slits, , wall-head defenses such crenellation and, in more advanced cases, machicolations, aimed @ active style of defence. krak des chevaliers in syria best preserved of concentric crusader castles. contrast, château pèlerin not concentric castle, side facing sea did not require defensive walls. however, 2 walls facing land built on same defensive principles other crusader castles in same period, rivalling defences @ krak.

while concentric castle has double walls , towers on sides, defences need not uniform in directions. there can still concentration of defences @ vulnerable point. @ krak des chevaliers, case @ southern side, terrain permits attacker deploy siege engines. in addition, gate , posterns typically strengthened using bent entrance or flanking towers.

concentric castles expensive build, powerful military orders, hospitallers , templars, or powerful kings, afford build , maintain them. has been pointed out concentric layout suited requirements of military orders such hospitallers in resembling monastery , housing large garrison. such castles beyond means of feudal barons. concentric castles coexisted simpler enclosure castles , tower keeps in crusader states.

concentric castles appeared in europe in 13th century, castles built in wales edward providing outstanding examples, in particular beaumaris castle, perfect concentric castle , albeit unfinished. beaumaris built on flat terrain rather spur, both necessary , possible build walls , towers facing in directions, giving regular, square, floor plan castle. influence crusader fortification has been conjectured, amount of technology transfer east , earlier byzantine examples remains controversial among historians.