Editing Concentric castle (section)

==Similar structures==

In the German-speaking states of the [[Holy Roman Empire]], many castles had double curtain walls with a narrow ward between them, referred to as a {{lang|de|[[Zwinger]]}}. These were added at vulnerable points like the gate but were rarely as fully developed as in the concentric castles in Wales or the Crusader castles.

The principle of an outer and inner wall was also used in fortified cities, such as the [[Theodosian Walls]] of [[Constantinople]] and the city wall of [[Carcassonne]].

The concept of mutually reinforcing lines of defence with flanking fire was continued in later periods, such as the early modern fortifications of [[Vauban]], where outer defence works were protected and overlooked by others and their capture did not destroy the integrity of the inner [[Citadel]].

Citadels from before and during the Reconquista in Spain and Portugal also have fortifications similar to concentric castles found elsewhere in Europe. [[Castle of Almodóvar del Río]] is a good example of such a fortress along with [[Sao Jorge Castle|Saint George Castle]] in [[Lisbon]] Portugal.