The accounts of Robert of Artois from 1314 give a good idea of the economics: “for a pound of silk bourre for Robert’s aketon, 6 s.; for 2 pounds of cotton to put in the said aketon with the aforesaid bourre, 4 s.; 5 ells of white linen for Robert’s aketon, price 2 s. 6 d. the ell, 12 s. 6 d.”

The aketon could be simple with just a facing and a lining, or it could be made twice with an interfacing and an interlining, I am not sure. But we know it makes one aketon and we have the prices for all three typical components.

• 2-4 layers of linen: 12 s. 6 d (150d)
  So 12-24 layers of the same linen would cost 900d
  
• 3 pounds of cotton: 6 s. (72d)
  
• 3 pounds of silk bourre: 18 s. (216d)

So a finger-thick aketon stuffed with raw cotton would cost 72 + 150 = 222d, the same aketon of layered linen would cost 900d. Even if they saved money by buying used linen (and the guild rules go back and forth about whether that is acceptable) it would probably be significantly more expensive. Fitzclarence noticed the same thing in India in 1819: "The irregular cavalry throughout India are mostly dressed in quilted cotton jackets; though the best of these habiliments are not, as I supposed, stuffed with cotton, but are a number of cotton cloths quilted together."

I just went through my collection of Byzantine military manuals and realised with some embarrassment that I misremembered the felt headwear as felt armour. The case for felt armour has taken a serious battering. I'd guess David Nicolle would be the best bet to determine what the exact term used by Baha al-Din. Anyone have a copy of Crusader Warfare Volume 1?

Thanks also for translating that passage. It definitely sounds like improvised armour and fits into the scheme you've proposed. I think I'll keep a salt shaker next to any book by the Bachrachs.

I think someone who was willing to go beyond the Arabic, Syriac, and Turkish sources which arms and armour people have talked about for 70 years could find lots of things. Every year there are more translations published and you just need a couple of years of evening courses to use a dictionary! But my Near Eastern languages are things like Aramaic and Sumerian not these newcomers.

Nicolle's Medieval Warfare Sourcebook Volume 1: Christian Europe and its Neighbours pages 76-78 list Greek zaba and Arabic jubbah plus Turkish kazāghand =(= jazeran/jazerain/jazerant?) Pages 165-167 on the high middle ages don't add any words.

There also seems to be some dispute whether Medieval Greek zaba is related to Arabic jubbah or to a word from the Eurasian steppes:

Suda On Line entry for 'zaba' wrote:

The term ζάβα (and Latin zaba), probably a loan from an Altaic language, occurs in historical and legislative sources from the early sixth century CE, and is especially frequent in late antique and Byzantine military treatises. For sources and discussion see Haldon (1975) 19-21, 37 n. 126; Kolias (1980); (1988) 37-43, 65-7. References: J.F. Haldon, 'Some aspects of Byzantine military technology from the sixth to the tenth centuries', BMGS 1 (1975) 11-47 T.Kolias, 'Ζάβα, Ζαβαρεῖον, Ζαβαρειώτης', JÖB 29 (1980) 27-35 T.Kolias, Byzantinishe Waffen. Ein Beitrag zur byzantinischen Waffenkunde von den Anfängen bis zur lateinischen Eroberung ([Byzantina Vindobonensia 17] Vienna 1988)

The Suda (a lexicon/encyclopedia last updated in the 10th century) equates zaba and λωρίκιον lorikion "little lorica" which is usually thought to be mail.

Other sections of the Medieval Warfare Sourcebook mention tijfāf "felt barding" and the kārwa or gārwa of quilted leather stuffed with cotton in modern Afghanistan.

We have so many more sources from Egypt/Syria/Iraq than the Greek world that I would expect there to be evidence for quilted armour in the east before Leo Vi's tactica in the 10th century. Al-Ṭabarī and Al-Tarṣūṣi seem to be two names to look up but its too far from my own areas of research!

I didn't manage to track down a copy of the first volume of Nicolle's Crusader Warfare, but I did track down his thesis, The military technology of classical Islam. In Volume I, p180, he mentions the term libd/labūd which means "felt hauberk" or, alternatively, "felt lining of a khazāghand" with Bahā al-Dīn as one example. I don't know whether it relates to our specific example (lack of language skills or original source), but if it does I can see where a potential mistranslation may have occurred.

Crusader Warfare Volume 1 doesn't seem to be available digitally and my library is unlikely to get back to me on the inter-library loan request for a couple of months, so it will probably be a while before I can get my hands on the source most likely to answer the question.

Re: zaba, p1-2 of this paper has a late 7th century Visigothic use of the word, although nothing that clarifies what it was exactly. Haldon, however, is quite sure that zaba and lorikion are both words for long coats of mail or lamellar armour, rather than small ones. The only exception seems to be the 6th century anonymous treatise (now redated to the late 9th century), which uses the term for textile armour, but in light of the redating it can't be certain that the "zaba" was originally textile armour.

The himation (in classical usage "cloak" but I don't know what it means later) a finger thick to stop weapons which penetrate the iron in the anonymous on generalship is interesting. That passage has been on the list of Armour in Texts for two years, but its a long list, and making sense of material culture in medieval Greek is hard work. Sometimes they sweat to write only words and case endings Plato would have recognized and sometimes they just stick an -ion on the Arabic or Italian word they actually say. The Lexikon zur Byzantinischen Gräzität has entries for gounion "gown" and zoupa "jupe" which is exactly like a Frankish scribe writing <aketon-um> or <dagar-dus>.

Edit: I think what DN was getting at was the possibility that the zaba had an integral liner.