Roman Metalworking

[Ron Andrea]

If large quantities of high-quality steel was not available until the eighteenth and nineteenth centuries, how did Rome equip its huge armies with weapons and armor? I realize that it wasn't all done at once, but several military disasters led to the formation and equipping for multiple legions.

Can anyone suggest a good book on Roman metalworking technology--equipment, methods, locations?

[Matthew Amt]

Ave!

You want "Iron for the Eagles" by David Sim. And who says large amounts of iron and steel were not produced? Armor for a quarter-million men sounds like a lot to me. Sure, it's not as much as you need to build fleets of iron ships with cannons, and railroads all over the world with iron bridges, but for the technological level and population involved, the Romans did pretty darn well. Recent studies show that Roman armor used better steel than most medieval armor until the Renaissance. It didn't have to be "high quality" to be good armor, in any case.

There are cases all through history of large armies being equipped surprisingly quickly--it wasn't just the Romans who could do it. (Though of course since they tended to have more armor than most others, it makes it that much more impressive for them!)

When I imagine how long it took a Roman craftsman to make something, I generally figure it was much faster than a modern craftsman could do it. Don't get me wrong, some of our present-day armorers are darn good! But they'll typically work alone, on one object at a time, and they often have to take extra time trying to match a particular artifact. But back then, the armorer would have a couple assistants, and could be pounding on one helmet while another reheated in the forge. He didn't have to match anything exactly, just aim at the form he wanted and hit anywhere in the ballpark just by experience. One of his assistants could be cranking out rivets and brass bits, while another would do the finishing work. I wouldn't be surprised to see a shop like that produce several helmets per day.

Also, not all legionaries wore body armor, so a rapid equipping of new legions might involve sending them out with a higher percentage of unarmored men. And of course in the Republic the typical body armor was the pectoral, not a lot of metalwork at all compared to a hamata or segmentata!

Vale,

Matthew

[jvrjenivs]

You might also want to wait another 2-3 months, untill a new book on the subject will be published
http://www.oxbowbooks.com/bookinfo.cfm/ID/90894

[Eleatic Guest]

Roman iron production - as well as in other metals - was second to none in antiquity: http://en.wikipedia.org/wiki/Roman_economy#Industry

[Ron Andrea]

Great. Sounds just like what I need.

The history books claim that prior to development of the Bessmer blast furnace process only limited quantities of high quality steel was possible. Of course, as Matthew said, it depends on how you define large quantities.

I'll be looking for both books.

Gratias ago vos.

[john roberts]

Don't forget that, as Rome expanded, it acquired more iron mines and the people to work both the mines and the metal. People were part of the loot. Once in Spain, the Romans got the fabulous iron mines near Toledo that produce superior sword steel to this day. The Gauls were the premier iron workers of their day and when Caesar conquered Gaul, Rome got all those Gallic armorers as well. Northern Italy (part of Gaul at that time) set the fashions in armor from the early Middle Ages to the end of the time armor was worn.

[Marcus Velius Avitus]

Indeed - Roman iron ore was available from multiple sources throughout the empire. They mined locations in Europe that are still large iron sources. The Bessemer process really did speed up the process, but it made steel production more consistent - and more importantly, it made mild steel as cheap as wrought iron. This made steel the natural choice for cosntruction and it is to this day. Try finding wrought iron nowadays - No one produces it. If you find some old wrought iron, save it like it is made of gold! Blacksmiths love it because it forge welds so nicely. The higher carbon content of mild steel(the closest thing most blacksmiths have access to like old iron) will literally "burn" at the temperatures necessary for forge welding, making it a difficult tightrope to walk between welding and burning for the modern smith.

I'll bet the Romans still probably had large scale smelting operations making iron bar stock (and possibly sheet and plate). There had to have been large enough sources for suppliying Rome's legions. The increased challenge of making large quantities of iron and steel "the old fashioned way" could have been offset somewhat by slave labor too? I really don't know. I have read that a lot of mining was done by slaves. Perhaps iron production was similar? I sincerely doubt that a government as large as that of the Roman Empire would have contracted its iron supply from small localized iron sources. I just bet that the state had a hand in it somehow. If for no other reason, it would have been extremely lucrative! Everybody needs iron. You set the prices, you win. That isn't based on any eveidence whatsoever though! I'm just speculating!:lol:

[Dan Howard]

This is a pretty good summary of Roman mining techniques
http://www.unc.edu/~duncan/personal/roma...mining.htm

Look up Rio Tinto. It has been estiamted that the Romans left behind 6.6 millions tons of slag from their smelting operations on that site alone. Healy estimated that the Roman Empire consumed around 82,500 tons of iron each year.

[Marcus Velius Avitus]

Wow - thats awesome! 82,000 tons - WOW!

[Crispvs]

At the Carlisle Millennium conference David Simm described a scale which had been found during the Millennium excavations. This scale had been tinned on one side only and the iron it was made from contained virtually no slag.
It was plausibly suggested that the tinning could have been achieved by sticking scales back to back and then tinning them, but the purity of the iron was more difficult to explain. Simm said that the purity of the iron was so high that it strongly resembled poured iron, but he felt he had to discount this possibility on the basis that the Romans could not have been able generate the temperature required to achieve this. Simm believes that the Romans always used charcoal for their iron working and as he says, it would be close to impossible to produce the necessary temperature to create molten iron which was sufficiently liquid to be successfully poured using charcoal. He said that it would have taken coal to achieve the necessary temperature and he does not believe that Roman smiths had access to coal.

However, he may be wrong about this. When Rob Travers was close to completing his doctorate (on the use of coal by the Romans) he told me that the assumption that the Romans did not use coal was widespread and had led to finds of coal being sidelined or explained away. He said that virtually all the dig reports he had read on sites with hypercausts or bath houses had shown evidence of coal, often listed very last with the words 'and some coal dust was also found' or similar. He said that at one site lumps of coal had actually been found which were small and broken as one would expect of mined coal but it had been explained away as glacial erratics, even though one would expect erratic coal to be found in much larger pieces. This evidence suggested to him that there was an active Roman coal industry but that, naturally, most of the evidence would have gone up in smoke (literally).
Of course, Dr Simm is not always of the mildest disposition and in my experience he does not react particularly well to having his statements questioned (I was unlucky enough to unintentionally get on the wrong side of him once), so I daresay the new book will probably not give much more thought to coal than the last one, even though the implications for our understanding of Roman iron production are quite significant.

Crispvs

[PhilusEstilius]

I think that the best authority on the subject of Roman iron would come from the papers of the late John Ansty, for he indeed did smelt Roman iron in it's true fashion.

[mcbishop]

Simm said that the purity of the iron was so high that it strongly resembled poured iron, but he felt he had to discount this possibility on the basis that the Romans could not have been able generate the temperature required to achieve this. Simm believes that the Romans always used charcoal for their iron working and as he says, it would be close to impossible to produce the necessary temperature to create molten iron which was sufficiently liquid to be successfully poured using charcoal. He said that it would have taken coal to achieve the necessary temperature and he does not believe that Roman smiths had access to coal.

David has said to me he thinks he could now make molten iron using Roman technology and is embarking on a project to do just this. However, are you absolutely sure he said

he does not believe that Roman smiths had access to coal

because the Roman use of coal has long been known and Martin Dearne undertook a project with Keith Branigan on it* back in the 1990s?! I have a memory of David saying they did not have coke at the Carlisle Millennium shindig which is true (it requires a modern manufacturing process to make it) and the impurities in coal (which are what the coke-making process removes) make it impossible to make iron of that purity in that way, hence the use of charcoal (which lacks those impurities).

Of course, Dr Simm is not always of the mildest disposition and in my experience he does not react particularly well to having his statements questioned

Pah! He's a pussycat. You just have to know the safeword (fans of Serenity will get it). ;-)

*Dearne, M. and Branigan, K. 1995: 'The use of coal in Roman Britain,' Antiquities Journal 75, 71-105

Mike Bishop

[Marcus Velius Avitus]

This is indeed a very interesting topic.:grin:

I wondered about if the Romans were actually mining bituminous coal or anthracite out of veins or if they were making and using mostly wood coal (charcoal) as it is beleived that many other anicient peoples did. Coal veins sometimes run near the surface and might have been accessable. This article given to me in another thread is pretty cool:

Roman Mining

It describes different mining techniques for metals specifically. Was this going on for minerals and coal too? As a blacksmith, wood coal burns hotter than stone coal and produces good welding temeratures, but burns up much faster and it is still a huge pain in the neck to make it in any kind of quantity. I was fortunate enough to work at a living history museum where we regularly made charcoal. I can attest to how much work this is too. Easily as much labor as mining it out of the ground: You have to fell trees, split down lumber, stack it up, build the charcoal oven, burn it for days and days until it has cooked all the volitiles out and then uncover the whole mess and break it into pieces and transport it. This compared to digging and extracting - its probably comparable. "Stone" coal is also more consistent, stable and burns slower(easier to control heat).

[Dan Howard]

The Chinese definitely were making cast (puddled) iron during the Han Period and some items allegedly dating back to the Zhou period are thought to have been cast.

[Dan Howard]

You have to fell trees, split down lumber

Usually these processes were not needed. A lot of medieval charcoal was made from fallen timber or coppiced branches; the trees were left standing (don't know about Roman practices). Agreed with the rest of it. Charcoal makers regularly stayed awake for days at a time to keep an eye on the pile.