The gambeson functioned as a critical component of the medieval arming sequence, serving primarily as a shock-absorbent layer beneath metallic defenses. Constructed from multiple layers of linen or canvas and stuffed with materials such as horsehair, wool, or scrap cloth, its vertical quilting prevented the internal padding from shifting. For the high nobility, the garment was essential to mitigate the blunt force trauma of strikes that mail or plate would otherwise transmit to the body, and often integrated leather points for tethering limb defenses.
In a heraldic and social context, the gambeson represents a bridge between the heavily armored elite and the common levy. While the knightly class utilized the gambeson (or 'aketon') as a foundation, the wealthier peasantry and professional men-at-arms often wore it as their primary defense. By the 14th century, the garment evolved into the 'jupon' or 'pourpoint,' which frequently bore the wearer's heraldic achievements or liveried colors, thus transforming a functional piece of under-armor into a visible symbol of feudal identity and lineage.