|Coif and Helm Padding|
Most manuscripts and sculptures, c1240 - 1250 AD, show a much rounded top to the mail coif. This was shaped by a padded cloth cap, an Arming Cap, which was commonly much more thickly padded than originally thought. It is now believed that the lining or padding which was attached to the inside of the Helm would have been shaped or custom formed to fit the shape of the now heavily padded mail coif once the helm was in place on the head.
Research has shown that great helms, which were worn on top of the mail coif, would need a very secure, tight foundation, custom fitted to match the contours of the head, in order to prevent any movement of the helm whatsoever. Otherwise, the slightest blow to the head would shift the helm, thereby moving the eye slits and effectively "blinding" the knight. For this reason, the head padding was much more sophisticated and customized than originally thought, and highly sophisticated arming caps were in common use in the 13th century.