An example of a Sally port, here is the main entrance to Fort McHenry, in Baltimore, Maryland.

A Sally port is a small, easily secured door in a castle wall or other fortification. During a siege, defending raiding parties would "sally forth" from these ports and attack the besiegers. These raids would attempt to slow the offensive siege process. Targets for these raids included tools which could be captured and used by the defenders, labour-intensive works such as trenches and mines, and siege engines and siege towers. Sometimes enemy labourers were also targeted. ImageMetadata File history File links Download high resolution version (1920x2560, 839 KB) Licensing File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... ImageMetadata File history File links Download high resolution version (1920x2560, 839 KB) Licensing File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Fort McHenry, in Baltimore, Maryland, is a star fort best known for its role in the War of 1812, when it successfully defended Baltimore Harbor from an attack by the British navy in Chesapeake Bay. ... Baltimore skyline at dusk Motto: The Greatest City in America (formerly The City That Reads; BELIEVE is not the official motto but rather a specific campaign) Nickname: Charm City Mob Town B-more Location in Maryland Founded Incorporated 30 July 1729 1797  County Independent city Mayor Martin J. OMalley... The Alcázar of Segovia, Spain A castle (from the Latin castellum, diminutive of castra, a military camp, in turn the plural of castrum or watchpost), is a fort, a camp and the logical development of a fortified enclosure. ... Nakhal Fort, one of the best-preserved forts in Oman. ... For the Boston area punk band see Siege (band). ... A siege engine is a device that is designed to break or circumvent city walls and other fortifications in siege warfare. ... A siege tower is a specialized siege engine, constructed to protect assailants and ladders whilst approaching the defensive walls of a fortification. ...

A "Sally Port", derived from the French words for room "salle" and door "port", is a small controlled space with two doors. Essentially, one must enter the space and close the first door before opening the second to proceed. Modern sally ports are used to control entry into highly classified areas and a guard will often occupy the middle space checking credentials of anyone wants to pass through the second door. Sally ports are also used to restrict the flow of people to one at a time so that intruders cannot pass into the classified area on a cleared person's coat tails. Sally port may also be from the latin 'salire' meaning to rush

Source

• Continuing Education Program - Royal City of Eoforwic