A gambeson also known as aketon, padded jack and arming doublet etc. is a padded defensive jacket, worn as armour separately, or combined with mail or plate armour. Gambesons were produced with a sewing technique called quilting. They were usually constructed of linen or wool; the stuffing varied, and could be for example scrap cloth or horse hair. During the 14th century, illustrations usually show buttons or laces up the front.
An arming doublet also called aketon worn under armour, particularly plate armour of 15th & 16th Century Europe, contains arming points for attaching plates.The gambeson was used both as a complete armour unto itself and underneath mail and plate in order to cushion the body and prevent chafing. It was very insulating and thus uncomfortable, but its protection was vital for the soldier
There are two distinctive designs of gambeson: those designed to be worn beneath armour, and those designed to be worn as independent armour. The latter tend to be thicker and higher in the collar, and faced with other materials, such as leather, or heavy canvas. This variant is usually referred to as padded jack.