An ''arming cap'' was a padded fabric hood that became popular amongst the peasantry during the 13th century. It originated as quilted version of civilian

coif A coif () is a close fitting cap worn by both men and women that covers the top, back, and sides of the head. History Coifs date from the 10th century, but fell out of popularity with men in the 14th century."A New Look for Women." Arts and ...

and was worn under the helmets of 12th century knights. Fezzes were worn as arming caps.

References

Caps Medieval European costume Medieval armour {{clothing-stub