That is, leathers which are appropriate for Viking-Age reenactments is a fairly straight forward subject. For the most part, leathers of the period were brain, alum or vegetable tanned (tawed is a term used to describe a hide tanned with fur kept on one side) and were not specifically dyed another color, so the leather as generally brownish or a light tan. There is an indication that some of the leather found in York was dyed or painted red, but this remains controversial. It is safer just to assume that the leather would not be colored, and it certainly would not be colored black even though finger oils, consistent wear and use of the leather will darken it into a fine patina.
It is sometimes difficult to find these leathers nowadays. Certainly chrome-finished leathers is more frequently found and is less expensive but at the same time is more anachronistic. Its use should be avoided unless you get special permission from your Authenticity Officer to substitute the chrome-finished leather for what should be used.
It is far easier to find out where leather would be used during the period. In the earlier days, leather and fur were commonly used for clothing, but this had mostly died out by the Viking Age and is today the province of bad cinema and worse reenactors. Leather was commonly used for ropes—which were not part of the outfit—and for shoes, for belts (men’s belts were invariable half an inch to an inch wide) and for other straps, although there is some indication that leather was used for trousers. Some translations of Ælfric’s Colloquy, for example, the translation used by Kevin Leahy in Anglo-Saxon Crafts, notes: “I buy hides and skins and repair them by my skill, and make of them boots of various kinds, ankle-leather shoes, leather breeches, bottles…”
The use of leather for smiths’ and other craftsmens’ aprons is logical, but no artefacts or literary evidence has been found for such usage!
As to whether leather was used beneath byrnies, it is hard to say. In fact, it is hard to say if anything was used as padding beneath byrnies at all, whether it was mere a padded gambeson, a firm layer of leather or fabric or a quilted gambeson. On the other hand, it little matters because whether the fighter in period wore a gambeson or not, the gambeson should be hidden beneath the modern reenactor’s byrnie and should not only be viewed with difficulty but virtually unseen at all. What this means, very simply, is that when the reenactor removes the byrnie back at the wic after the combat, the public should not see the gambeson if such a thing is worn!
An essential work from the York Archaeological Trust, Leather and Leatherworking in Anglo-Scandinavian and Medieval York, is available for a free download.// //