From about the 12th century knights often wore flowing surcoats over their armor, they usually extended to the knee or about mid-calf. A knight's surcoat often displayed his device (origin of the term "coat of arms") which helped to identify him in the heat of battle, especially with the limited visibility offered by the great helm's of the period. For ease of movement surcoats were normally slit at the front and back, although some surcoats also had slits at the sides.
Modren reenactors and members of the SCA often also wear surcoate's to designate specific office holders such as Herald's in court and to make it easy to identify officials such as Marshal's and Medics at tournaments and on on the battlefield
Normally we make these in a solid color and they often are embellished with Embroidery or of Applique. For Fighting wear we normally use heavy weight fabrics, while court garb can run the gambit from Cotton to Linen and Silk.
