A curtain wall is a

defensive wall A defensive wall is a fortification usually used to protect a city, town or other settlement from potential aggressors. The walls can range from simple palisades or earthworks to extensive military fortifications with towers, bastions and gate ...

between two fortified towers or

bastion A bastion or bulwark is a structure projecting outward from the curtain wall of a fortification, most commonly angular in shape and positioned at the corners of the fort. The fully developed bastion consists of two faces and two flanks, with fi ...

s of a

castle A castle is a type of fortified structure built during the Middle Ages predominantly by the nobility or royalty and by military orders. Scholars debate the scope of the word ''castle'', but usually consider it to be the private fortified r ...

fortress A fortification is a military construction or building designed for the defense of territories in warfare, and is also used to establish rule in a region during peacetime. The term is derived from Latin ''fortis'' ("strong") and ''facere'' ...

, or town.

Ancient fortifications

Evidence for curtain walls or a series of walls surrounding a town or fortress can be found in the historical sources from Assyria and Egypt. Some notable examples are ancient Tel Lachish in Israel and Buhen in Egypt. Curtain walls were built across Europe during the Roman Empire; the early 5th century Theodosian Walls of

Constantinople la, Constantinopolis ota, قسطنطينيه , alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth ( Old Norse), Tsargrad ( Slavic), Qustantiniya (Arabic), Basileuousa ("Queen of Cities"), Megalopolis ( ...

influenced the builders of medieval castles many centuries later.

Curtain wall castles

In medieval castles, the area surrounded by a