A
passageway through a scarp wall used as a route of communication from one
part of the fortification to another. In permanent fortifications posterns
were usually, but not always, vaulted galleries positioned at the central
point of curtain walls of the enciente to allow easy access to the demi-lune
and other outworks. Unlike sally-ports, which were the main entrance and
exits to fortifications, posterns were primarily intended for internal
communications necessary for the defense of a fortification's outworks. Posterns
were not generally employed in field fortifications though they were used
in some larger well developed semi-permanent works that were covered by outworks.
An unusual arrangement in the working plan of Fort Morgan, Alabama
in which the flank casemates of the bastions served as posterns that opened
on the faces of the bastions. Only one of these posterns remains.
A
passageway through a scarp wall used as a route of communication from one
part of the fortification to another. In permanent fortifications posterns
were usually, but not always, vaulted galleries positioned at the central
point of curtain walls of the enciente to allow easy access to the demi-lune
and other outworks. Unlike sally-ports, which were the main entrance and
exits to fortifications, posterns were primarily intended for internal
communications necessary for the defense of a fortification's outworks. Posterns
were not generally employed in field fortifications though they were used
in some larger well developed semi-permanent works that were covered by outworks.
