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"Curtain, in Fortification, is the portion of rampart or wall between two bastions or two gates. In a regular siege, to batter down the curtain is one of the main operations depended on; and many of the external works constructed by the defenders are intended to frustrate, or at least embarrass, this operation. In the annexed cut, which shows a ground-plan of some of the elements of a regular fortification, FF' is the curtain; HAEF, a bastion. The component parts of the bastion are thus designated: AH and AE, two faces; EF and GH, two flanks; A, the salient; FG, the gorge; and H and E, the shoulders. mn is the rampart; mo, the parapet on the rampart; QPQ', the ditch; NO, the covery-way; RWR', the glacis; KLL', a ravelin." — Chambers' Encyclopedia, 1875

Curtain

"Curtain, in Fortification, is the portion of rampart or wall between two bastions or two gates. In…

Ramparts or limes, defensive walls or fortifications constructed for defense of ancient cities or settlement from aggressors. Some constructed as early as the 1st century A.D. when the Romans conquered the land and defended their position there by constructing a rampart (limes). A limes (or the Limes Romanus) was a border defense of Ancient Rome. It marked the boundaries of the Roman Empire. In ancient to modern times, they were used to enclose settlements. Generally, these are referred to as city walls or town walls.

Ramparts of Ulm

Ramparts or limes, defensive walls or fortifications constructed for defense of ancient cities or settlement…