Linothorax vs Quilted linen vs spolas

[Dan Howard]

Alan Williams, author of "The Knight and the Blast Furnace" documentented the effectiveness of 16 layers of linen armour against cuts of the sword and thrusts of the spear, and found that a mere 50 Joules of energy is needed to penetrate the fabric with a spear, and 80 for a sword cut. Over 25 layers were require to defeat a sword cut in the midrange of energy for an effective sword cut (140-220 Joules)

I'm more than aware of WIlliams' book and cited from that chapter often enough. Nowhere does he state how his padding was constructed. My own experiments indicate a far higher resistance to penetration which increases as the spacing between rows of stitches decreases. If the individual layers are rotated to, say, 45 degrees so that the weft and warp run in different directions then resistance can be improved even further.

You also mention leather armour being very rare in North-western Europe. As leather armour was widespread enough to to lend its name "cuirasse" in French and English to armour in general, your position isn't terribly tenable.

Consider, when Edward the first and his friends have a tournament in cloth armour with light weapons at Blythe in 1258, William Longsword and Robert de Quincy are killed, and Roger Bigod has his faculties permanently impaired. And they were friends.

Subsequently Edward comissioned suits of cuir bouilli armour from existing leather armour makers for tournaments, which served quite well.

Leather body armour saw use for a very very limited period of time on Western European battlefields and other than that saw use only in tournaments.

As mail armour begins to be less adequate during the middle ages, it is widely supplemented by leather armour throughout north western Europe and elsewhere. Leather breastplates (cuirasses) are among the first additions, and cuisses (thigh armour) as second. Both names are based on their origins as leather armour in north western europe.

As stated above leather saw very limited use for a very limited time and even during this time textile armour was far far more prevalent.