The real costs of making money (6). The Roman denarius.
“Render unto Caesar the things that are Caesar’s”
Introduction. These posts loosely use the concept of the ‘life cycle analysis’ of a product and apply it to one of the stages of the product ‘silver or golden coins’, i.e. the mining of the silver/gold needed to produce these coins. And bitcoins. They depart from ‘normal’ life cycle analysis in the sense that they do not look at for instance the amount of energy used or carbon dioxide produced during this stage of production but at the labour market institutions which governed the division of labour in the silver mines was mined. This silver/gold which, turned into coins, was used to organize and expand empires was often mined by slaves, prisoners of war, convicts or ‘feudal labour’ (like the Inca mita system, which was used by the Habsburg empire to recruit labourers for its South American mines). Today: the Roman denarius. First, some iconic ‘Roman’ transactions will be discussed to give the reader an idea of the role of money in the Empire. After this, some remarks on the institutions governing the use of labour will be made. The posts are explicitly written with the aim to rebuke the ‘markets led to money’ myth which (often in the shape of ‘the classical dichotomy’) is still prevalent in many economic textbooks: looking at the entire life cycle of money depicts a harsher and much more state based reality. Earlier posts can be found here (the Athenian owl), here (the silver used to buy Josef) here (the piece of eight), here (South African gold) and here (Bitcoin). Aside: the investigation below is based upon ancient Roman and Jewish texts, Greenland ice cores, Iberian slag heaps and much more which provides us with remarkable precise information about silver (lead) production and Roman money – but gives only a vague idea about ‘the life of the miners’. I did not encounter one estimate of the number of silver miners, for instance – but that might of course be due to me being an ignoramus when it comes to ancient economic history.
In the Roman empire, different kinds of money were used
“On entering the house, they saw the child with Mary his mother; and they knelt down and paid him homage. Then, opening their treasure chests, they offered him gifts of gold, frankincense, and myrrh. And having been warned in a dream not to return to Herod, they left for their own country by another path.”
Matthew 2 11:12
“Then one of the twelve, named Judas Iscariot, went to the chief priests and said, “What are you willing to give me to betray Him to you?” And they weighed out thirty pieces of silver to him. From then on he began looking for a good opportunity to betray Jesus”
Matthew 26 14:15 (translations differ in the crucial translation of the word ‘weighed’. ‘Counted’, ‘Paid’, and ‘Gave’ are also used).
Are these, in western culture, the most iconic transactions ever? The first was a ‘gift exchange’ act, exchanges which are not about transferring wealth but among other things about transferring ‘prestige’ and which are based on or try to establish or recreate trust and social bonds and relations. The second is a ’market exchange’ transaction which, in this case and surely upon closer inspection, is all about treason. This closer inspection yields that in the Jewish temple priests were not allowed to use Roman money, which showed the emperor as a semi deity. These thirty pieces used to pay for betrayal were not Roman money but ‘kosher’, money. While, in the Old Testament, thirty pieces of silver is the price of a slave. And there is more to this: it was Jesus himself who cleansed the temple from money changers and traders, money changers who no doubt exchanged kosher money for Roman money? According to Jesus only ‘gift exchange’ could take place in the temple while he explicitly stated that not silver or copper but the context of the gift made it valuable… And this sacred money, tied to a trust based gift culture, was used to pay for – treason. The ‘Render unto Ceasar the things which are Ceasar’s and unto God the things that are God’s‘ which Jesus told to the Pharisees when they asked them if they had to pay taxes, and after Jesus had asked them to show a denarius, was, considering the information above, not meant to tell them to pay taxes but a way to reframe the discussion from a political one to a spiritual one and to chide the Pharisees that they even had such unholy money. But enough preaching. The denarius clearly was the official money which embodied the power of the Roman state. Our questions are where the silver used to make Roman and Jewish coins came from, who owned the mines, who produced it and how this was organized. The answer is: it came at least to a large extent from the Rio Tinto mines in southern Spain which were owned by the Roman state and while we do know how it was produced in a technical sense we do not really know how production was organized (but the ‘ad metallum’, working in the mines till death, was a standard Roman penalty for minor crimes…).
Labour use in Roman mines: still a bit of an enigma
The Roman empire was quite late to start minting coins (third century BC). It might have been that until that time they lacked a dependable inflow of silver. I dare to disagree on this with the Wikipedia page on Roman currency, assessed 21-12-2015, which explains the rise of silver coins in the Roman empire after 226 BC, when the first silver denarius was struck, to cultural factors. Not long after the minting of this first denarius the Romans, during the second Punic war (218-201 BC) gained control over Iberia, i.e. Portugal and Spain (205 BC), which gave them access to the all-important and already ancient Rio Tinto mines in southern Spain. These mines were in ancient times mined by the indigenous population, later by the Carthagians and eventually, after 205 BC, by the Romans. The Romans had a knack for effectively applying existing technology to large scale projects. In this case ventilation shafts and drainage systems were built to enable deep vein mining (up to 200 meters) which enabled a considerable expansion of the Rio Tinto production of silver and lead (lead was a necessary as well as valued byproduct and also used in the process to extract silver, more about labor and the organization of the process below).
We know that Rio Tinto was the main source of silver in the Roman empire as (based on lead in Greenland ice cores): ‘Isotopic systematics point to the mining districts in southwest and southeast Spain as the dominant sources of this lead, giving quantitative evidence of the importance of these mining districts to the Carthaginian and Roman civilizations. Lead with a Rio Tinto-type signature represents ∼70% of the lead found in Greenland ice between ∼150 B.C. and 50 A.D.’ (Rosman e.a., 1997). According to this information, Roman production of metals was indeed impressive – it would take until about 1750 until its level of production of lead was surpassed.
Picture 3. World lead production
Source: this Wikipedia page assessed 18 December 2015, original source here.
According to Barry Yeoman: “The scale of mining at Rio tinto fundamentally altered the Roman economy… Rome used silver denarii to pay and feed its army, fund public building programs in its capital city, and subsidize the price of (and eventually allow free distribution of) grain to the city’s residents.” The discontinuation of silver production seems to have disrupted the monetary system. The decline of production of lead aligns with the decline of the silver content of Roman coins. At the end of the second century, the Roman empire lost access to the mines (because of an invasion by the North-African Mauri) and the silver content of the denarius which around 15 BC had been 97% dropped according to the precise estimates of Alan Pense after the year 170 from 80% to 60% while after about 250 it plunged to 2%.
The Rio Tinto mines were owned by the Roman state and managed by a ‘procurator’ (or sometimes a sub-procurator) who was directly appointed by the emperor and not responsible to the governor of Spain. We do not really know how labor in the Rio Tinto mines was organized. Roman writers were unanimous that work in the mines was grueling, look here. Tacitus even ranks it as one of the reasons for conquered people to revolt. Circumstances in the shafts (which could run up to 200 meters deep) must often have been appalling: cramped, hot, moist and pitch dark except for some oil lamps. We also do not really know who worked in the mines. I could not find any mention of the number of people working in or around the mines and A.J.M. Jones states on p. 838 of (Jones, 1964): ‘The organization of mining is most obscure’. Since Jones wrote some progress has been made but the picture still is as far as I could gauge far from clear. Evan Haley (1991) investigates all known tombstone inscriptions and the like in Spain which enable us to investigate where somebody who had deceased was born and finds (though he is not able to quantify this) that there was considerable interregional migration tied to mining locations, while it is also possible that entire villages were removed to mining sites by the romans and points to the possible existence of purely male villages near mines which probably housed seasonal workers. The archaeometallurgist Lorna Anguilano (2012) investigated the slag heaps of the Rio Tinto mines to investigate if these tell us something about the organization of work, her work contains a ‘state of the art’ overview of what we know about the organization of mining in Rio Tinto. The process was surely state led in the sense that the state granted concessions, took care of basic infrastructure and took its cut. Alfred Michael Hirt (2010) has published an exhaustive overview of all known literary sources about Roman mining (including tombstones and the like). He describes a process which, depending on geological and geographical circumstances, in the end was state led but which made extensive use of small and large subcontractors and, depending on circumstances, different kinds of free and coerced labour while occasionally army personal was used in the mines. As a rule, however, the soldiers did not have to work in the mines but to protect them. We have to keep in mind that the different stages of the process (digging, transporting the ore, crushing the ore, smelting) may have been organized in different ways and Anguilana suggests that the mines first were worked by slaves, later (when the wars of conquest came to a halt and new slaves became scarce) by families of miners and even later by the state who, using a simpler technology and less experienced workers, adapted to population declines caused by outbreaks of plagues as well as to dwindling resources of wood and charcoal. Also, as stated, the ad metallum, being sent to the mines, was a common sentence for petty criminals. The best original source we have about the organization of the trade are two bronze plaques who describe how concessions were granted and which are indeed quite enlightening and suggest extensive subcontracting. The plaques also state that miners had free access to the famous and important Roman baths. Which, for once, sounds good but these might have been (imo: were probably) the people who owned a concession, not the prisoners of war or the people convicted to ‘ad metallum’. My arguments: these concessionaires were able to raise quite a bit of money and to work five diggings at the same time, something which you can’t do as a single convict. See the excerpt below which, also considering what Hirt writes about these plaques, seems to be about the most important written source about the organisation of Roman mining (source):
“To Ulpianus Aelianus, greeting
In accordance with the will of the liberal and most sacred Imperator Hadrian Augustus, he shall make immediate payment. If anyone does not do so and is convicted of having smelted ore before paying the price as specified above, his share as occupier shall be confiscated and the entire diggings shall be sold by the procurator of mines. Anyone who proves that the tenant has smelted ore before paying the price of the half share belonging to the fiscus shall receive one fourth. Silver diggings must be worked in accordance with the details contained in the regulations. Their prices will be kept in accordance with the liberality of the most sacred emperor Hadrian Augustus, whereby the ownership of the share belonging to the fiscus belongs to the first person to offer the price for the diggings and pay down to the fiscus the sum of 4,000 sesterces. If anyone strikes ore in one out of five diggings he shall, as stated above, carry out the work in the others without interruption. If he does not do so, another shall have a legal right to take possession. If anyone after the 25 days granted for raising working capital actually begins regular operations but then stops operations for ten consecutive days, another shall have the right to take possession. If the diggings sold by the fiscus is idle for 6 consecutive months, another shall have a legal right to take possession, on the condition that when the ore is extracted therefrom one half shall be, according to customary practice, reserved to the fiscus.”
Summary: the Roman empire owned the mines and seems to have subcontracted mining, after taking care of basic infrastructure while different kinds of coerced and ‘free’ labour were used in the mines, depending on circumstances. Production of considerable quantities of silver enabled the Roman monetary system (and the Roman empire) to persist for quite and made it possible expand and organize the empire as well as to impose a ‘colonial’ Roman tax system on the conquered regions. Mining led to at least local deforestation and human costs were as far as we know high but we have next to no quantitative information about this.