In medieval castles the chemise (etym. fr. shirt) was typically a low wall encircling the keep

Keep

A keep is a type of fortified tower built within castles during the Middle Ages by European nobility. Scholars have debated the scope of the word keep, but usually consider it to refer to large towers in castles that were fortified residences, used as a refuge of last resort should the rest of the...

, protecting the base of the tower. An alternative term, more commonly used in English is mantlet

Mantlet

A mantlet was a large shield or portable shelter used for stopping arrows or bullets, in medieval warfare. A mantlet could be mounted on a wheeled carriage, and protected one or several soldiers....

 wall.

In some cases, entry to the keep was only accessible from the chemise (i.e. at the first floor level). Numerous examples exist of highly varied form, including the heavily fortified chemise of Château de Vincennes

Château de Vincennes

The Château de Vincennes is a massive 14th and 17th century French royal castle in the town of Vincennes, to the east of Paris, now a suburb of the metropolis.-History:...

, or the more modest example at Provins

Provins

Provins is a commune in the Seine-et-Marne department in the Île-de-France region in north-central France.Provins, a town of medieval fairs, became a UNESCOWorld Heritage Site in 2001.-Administration:...

, both in France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

. Some chemises are suggested to have been developed from earlier motte and bailey defences, though they may not usually be referred to as chemise.

In later fortification

Fortification

Fortifications are military constructions and buildings designed for defence in warfare and military bases. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs...

, a chemise is a wall with which a bastion

Bastion

A bastion, or a bulwark, is a structure projecting outward from the main enclosure of a fortification, situated in both corners of a straight wall , facilitating active defence against assaulting troops...

or any other bulwark of earth, is lined; for its greater support and strength.