Lorica segmentata leathering

[caiusbeerquitius]

Brain tanning, done worldwide afaik, is good for thin leathers, but requires that it be smoked to maintain water repellency...once it's become wet several times with insufficient smoking, it reverts to nearly a rawhide state, getting stiff and uncomfortable to wear.

"Brain tanning" is a misleading name. The tanning process is actually the smoking. The brain is used to enrich the skin with lipides, which then help to reserve the skin when it is "tanned" through the formaledehyde from the smoke. Actually it is not "tanned" at all in the very sense of the word´s meaning, if I understand it correctly. If you don´t smoke the skin enough it just is that: fat rawhide, which will loose the fat with each washing.

[John Conyard]

Yes, when I use the term vegetable-tanned leather, I mean leather tanned using tannin and other ingredients found in vegetable matter, tree bark, and other such sources. It is supple and brown in colour, with the exact shade depending on the mix of chemicals and the colour of the skin.

[Matt Lukes]

The problem is that the archaeological evidence dictates that vegtanned leather was not used for lorica seg internal leathering (it only ever turns up as mineralized remains and never in deposits where vegtanned leather items do survive)...

So the suggestion is that just because no straps are found in cases were definite vegetable tanned leather is found, it cannot be vegetable tanned leather? These other objects were in identical local conditions- i.e., in direct contact with iron and copper alloys, etc.? Not that I have reason to believe such conditions would aid degradation, but clearly anything that might contribute to the leather being differentially preserved has to be eliminated. Could it even be possible that there wasn't much there to begin with? Were these armour pieces significant groupings and not just lone plates that could have been detached from any leathering prior to deposition?

[mcbishop]

The problem is that the archaeological evidence dictates that vegtanned leather was not used for lorica seg internal leathering (it only ever turns up as mineralized remains and never in deposits where vegtanned leather items do survive)...

So the suggestion is that just because no straps are found in cases were definite vegetable tanned leather is found, it cannot be vegetable tanned leather? These other objects were in identical local conditions- i.e., in direct contact with iron and copper alloys, etc.? Not that I have reason to believe such conditions would aid degradation, but clearly anything that might contribute to the leather being differentially preserved has to be eliminated. Could it even be possible that there wasn't much there to begin with? Were these armour pieces significant groupings and not just lone plates that could have been detached from any leathering prior to deposition?

Exactly so. The internal leathers are preserved in the Corbridge Hoard because everything there is mineralised, even the feathers. The Carlisle Millennium deposit had none, despite being in anaerobic conditions that preserved a wide range of organic materials. The armguards were clearly deposited articulated yet there was not a single trace of leather strap within them, even caught under the rivets, and I had the conservator (who was very good) look very carefully for me. The Carlisle ferrous material had not started to mineralise anything around it and there was enough metal left for David Sim to polish up a section for metallographic analysis. The Corbridge Hoard was completely oxidised.

Don't forget the only 1st century cavalry harness (by which I mean the straps themselves, not chamfrons, saddles, or the like) we have is also only preserved in a mineralized form on the back of fittings like the pendants from Xanten in the BM.

Mike Bishop

[Crispvs]

Mike,

Do we know what treatment the leather which had been wrapped around the Carlisle assemblage had been given? I presume this would have to have been tanned with a different process to the missing leathering of the manicae to preserve it.

Crispvs

[Matt Lukes]

I'm not familiar with the constituents of the Carlisle Millenium find- were there articulated sections or parts of one or more L. segmentata present as well? Or is the suggestion that by extension other armours' leathering was likely similar to the armguards'? And is it the case that the other organics that were preserved are too diverse or otherwise clearly had no additional element, such as waterproofing treatment, that contributed to their preservation? Is there any other explanation than that the armguards' leathering must have been significantly different than the usual tanned leather? Is there any example of other than vegetable- or mineral salt-tanned leather from later in history? I'm only familiar with the usual types.

[mcbishop]

Do we know what treatment the leather which had been wrapped around the Carlisle assemblage had been given? I presume this would have to have been tanned with a different process to the missing leathering of the manicae to preserve it.

It wasn't so much a case of leather 'wrapped around' the Carlisle items as leather items in and around the armguards - so in close enough proximity to suggest that the armguard leathers should have survived if they were of tanned leather. Your presumption is the key to the nub of the gist of the kernel of the problem!

Mike Bishop

[mcbishop]

I'm not familiar with the constituents of the Carlisle Millenium find- were there articulated sections or parts of one or more L. segmentata present as well?

There were both articulated sections of armguard (i.e. all the plates were in the correct relation to each other as if still leathered) and individual pieces of segmentata (including the first near-complete Newstead backplate in a Hadrianic context - the other backplate from Carlisle was in a late context, thought at the time to be residual) in the Carlisle Millennium deposit.

Or is the suggestion that by extension other armours' leathering was likely similar to the armguards'?

Occam's Razor suggests this to be the case: leathering only ever survives on lorica seg as mineral preserved fragments (Corbridge Hoard, Kalkriese breastplate) so it was left on sometimes. When plates are found in conditions that preserve vegetable tanned leather, no such internal leather fragments are found. Either it is a massive coincidence that this is so, which seems unlikely, or different forms of treatment were being used.

And is it the case that the other organics that were preserved are too diverse or otherwise clearly had no additional element, such as waterproofing treatment, that contributed to their preservation?

None that was apparent during conservation. There was a diverse range of objects and offcuts so any notional special treatment would have to have been universally applied.

Is there any other explanation than that the armguards' leathering must have been significantly different than the usual tanned leather?

None that I can come up with. Occam's Razor suggests it is not necessary to look for an overly complex solution when a simple one exists.

Is there any example of other than vegetable- or mineral salt-tanned leather from later in history? I'm only familiar with the usual types.

Carol van Driel-Murray has in the past talked to me of other techniques of preservation used in historical circumstances (she has looked at a lot of medieval, as well as Roman, leather from the Netherlands) but I can't cite evidence on this, leather is not my thing, but I trust her opinion on this.

Mike Bishop

[Matt Lukes]

Thanks for all the clarification Mike. Indeed it's better (and rarer LOL) to search for a simple explanation rather than a complicated one- but I can't escape the issue that it seems the opposite to think they'd have used other than normal tanned leather for armour straps LOL Clearly regular leather works just fine so using something else just for armour seems more complicated...

[Caius Fabius]

i am having someinteresting results in using olive oil on rawhide and tanned leather. I am soaking untanned bull scrotums in olive oil, and turning them into pouches. I have also been using oak galls and olive oil to soften and preserve the rawhide, which may add some tanning to the process. I am currently working with 4 cowhides, as well, just letting them hang and become rawhide. In a few days I'll cut one into strips and then see if they stretch or hold their shape under normal wear and use. Some will be soaked in olive oil, some in olive oil with oak galls. After the rawhide has been out in the weather and rain and sun for a while, it becomes hard, and doesn't seem to stretch when it gets wet. More results will be forthcoming.

[jvrjenivs]

i am having someinteresting results in using olive oil on rawhide and tanned leather. I am soaking untanned bull scrotums in olive oil, and turning them into pouches. I have also been using oak galls and olive oil to soften and preserve the rawhide, which may add some tanning to the process. I am currently working with 4 cowhides, as well, just letting them hang and become rawhide. In a few days I'll cut one into strips and then see if they stretch or hold their shape under normal wear and use. Some will be soaked in olive oil, some in olive oil with oak galls. After the rawhide has been out in the weather and rain and sun for a while, it becomes hard, and doesn't seem to stretch when it gets wet. More results will be forthcoming.

Very interesting. Keep us informed. Looking forward to your further results.

[M. Demetrius]

I knew a fellow back in the days when I was doing Fur Trade era who used the untanned scrotum of a food goat kid for a ball bag. Gotta love it! .45 cal; held about five or six.

[Gaius Julius Caesar]

Wow, that goat must have had some size of knackers! hock: hock:
Must have been hard on the finish cramming those .45's in there! Isuppose if you arranged them muzzle first , in a star pattern, it might hace worked.....\\
Ohh, I see, .45 cal ball shot.....not that kind of ball bag then! :twisted:

[Caballo]

A very kind friend has given me a lorica segmentata that needs at least partial re-leathering- some straps broken, some torn. I'm extremely grateful and lucky!
Before I begin my winter project, could I have any tips from people who have re=leathered loricae before?
Regards
Caballo

[M. Demetrius]

Tip: drill out or grind the rivets from the inside.
Tip: Use good quality veg tanned leather strips.
Tip: Practice peening rivets on something less important, like scrap metal/leather, until you are sure you can make them hold.