It makes more sense than one might think to begin a discussion about the history of the market by returning to Ancient Rome. For, after all, not just the word market – but also merchandise, merchant, commerce, trade and even money are terms that ultimately derive from Latin. It is, however, a daunting task to survey this subject in brief: summarising the trade, culture and politics of an empire that not only spanned 13 centuries, but also covered most of Europe, North Africa and much of Asia, is not a task for the fainthearted.

What is more, the foolhardy figure who does make the attempt faces two additional difficulties from the outset. First, there is the messy complexity of reality: the ‘Roman market’ at times refers to a unified imperial schema dreamt up by the regime at Rome so as to be imposed across the empire; at other times it means the immense local variety that existed on the ground, a diverse kaleidoscope of regional – and in many senses independent – practices that began prior to Roman rule and never ceased entirely.

Second, there is the serious problem presented by gaps in our available evidence: most literary texts regarded trade as infra dignitatem – beneath their dignity – and the field of economics in the form we now understand it simply did not exist (despite the word’s derivation from the Greek oikonomia, literally oversight of the household). Most goods involved in trade were for consumption and therefore perishable, disappearing forever, a few weeks or years or centuries after they were bought and sold. Thus, the physical reality not just of goods but of market stalls and shops has mostly vanished without trace, as have almost all the records of sale once so carefully recorded on wax tablets or papyrus.

Yet evidence does survive to allow us to say some things that we know to be true. For many thousands of papyri accounts have fortuitously survived deep under the dry sands of Egypt, and hundreds of soldiers’ letters and bills have survived in the peat bogs of Hadrian’s Wall, near the border between (in our terms) England and Scotland. A yet bigger and more important survival was made possible – quite paradoxically – by the destructive eruption of Mt Vesuvius: when in AD 79 that volcano rapidly buried the town of Pompeii under burning ash, it paused in time an otherwise normal day of civic and commercial activity. The tangible, architectural remains of 600 shops survive from the town, as well as countless carbonised artefacts, frescoes depicting trade, and even several seductive advertising slogans.

Another mode of preservation-through-destruction is afforded by shipwrecks, which often conserve their cargo of ceramic amphorae, in some cases along with their original contents. The number of wrecked ships surviving in the Mediterranean from 100 BC to AD 300 is in fact so large as not to be equalled again until the Renaissance, one and a half millennia later. We can also study the skeleton of the Roman road network, the mind-bogglingly widespread movement of coinage, the distribution of particular potsherds, and the myriad Latin inscriptions spread around the empire. Finally, we can consult extant legal texts, including passages of Cicero’s speeches, which do on occasion talk directly about the grubby business of trade, as well as several handbooks on farming – that is on how the elite should manage their private estates. Much of major value can be inferred from all of this, although much remains speculative and often subject to alarmingly intense scholarly debate.

Let us begin, since all roads lead there, in Rome, though we should not take our first steps in the place one might naturally expect: that famous outdoor space at the heart of the city, between the Palatine and Capitoline hills, the Forum. For, although this was indeed Rome’s first open market, that situation had to change with time: if we were to transport ourselves back 2,000 years – to AD 24, say – we would find that this public space had become filled not with shops and stalls, but with religious temples, political and legal buildings, civic monuments; only in some parts of some buildings might we find upmarket commerce. Instead, most of the (literal) bread-and-butter activity of market life was, by the high point of Classical Rome, occurring elsewhere.

To witness produce changing hands, we have to wander to the various dedicated markets dotted around Rome: the Forum Boarium for cattle, leather and milk, the Forum Suarium for pork, the Forum Piscarium for fish, the Forum Lanarium for wool, the Forum Pistorium for bread, the Forum Vinarium for wine, the Forum Holitorium for vegetables and fruit, or the Forum Cuppedinis (literally the Market of Desire) for delicatessen fare; in addition, multiple macella (butchers) were scattered across the city. As for slaves, which accounted for up to a third of Rome’s human populace, both their great expense and importance meant that they were sold in the Forum itself, just by the ancient Temple of Castor and Pollux. Normal market trade was thriving in Ancient Rome, but on a scale that required specialisation in distinct centres all around the city.

Instead, a rather more instructive place to begin lies on a hill a little south of the Forum, on the east bank of the River Tiber. This is Monte Testaccio, which is not in fact one of the seven hills of Rome, or a ‘mountain’ at all: it is, in fact – as its alternative name Monte dei Cocci reveals – a rubbish tip of quite spectacular scale, made up entirely of broken shards from huge olive oil amphorae. Covering a footprint of five acres, it contains the remains of some 50 million amphorae, each of which contained 70 litres of oil. Alongside the sheer volume of evidence that this graveyard of some three or four billion litres provides, we should note that most of this oil came from the Roman province of Baetica in southern Spain, more than a thousand miles due west, with the rest having crossed the Mediterranean from the North African coast. Therefore, just this one site – apparently built because these particular amphorae were of a shape that rendered them unsuitable for recycling – can reveal the immense scale of Rome’s consumption, and the immense reach of its trade routes, even for a literally everyday product such as oil.

To put all this in some context, let us consider Rome’s inexorable expansion. The city had grown steadily since its legendary foundation by Romulus and Remus in the eighth century BC, and then rapidly from the third century BC. Although its growth was long restrained by rival military or mercantile powers, such as the Greeks, the Phoenicians and particularly (the latter’s upstart offshoot) the Carthaginians on sea, all that changed in the second century BC, when Carthage was destroyed and the Greeks were decisively defeated. Tellingly, after the Third Punic War, some Romans suggested that Carthage could simply rebuild herself, so long as the new city was set back from the sea and thus removed from maritime trade. A better plan still required only three words from Cato the Elder: Karthago delenda est, Carthage must be destroyed. And, in the self-same year of 146 BC, both Carthage and Corinth – the last outpost of the Greek threat – fell. From then on, the brakes were then off, and the Romans could uncontroversially call the Mediterranean Mare nostrum, Our Sea.

Did this new age of unbridled influence and control usher in an era of free-market, free-wheeling trade? Yes in principle, though not quite in practice. For this immense growth of Roman power and territory was not without problems and tensions, especially in the realm of trade. The traditional Roman attitude was that each family should farm their own land, in tranquil self-sufficiency. At the end of his long and laborious life, Cicero wrote in earnest that ‘of all the occupations by which profit is secured, none is better than agriculture, none more profitable, none more delightful, none more becoming to a free man’ (De officiis [On Duties], written in 44 BC). There was a sincere Roman belief in self-sufficiency – in the freedom of not being dependent on others.

As Rome expanded, she rapidly took control of ever more conquered farmland. But that captured land – in Italy, Sardinia, Sicily, Gaul and then yet further afield, although it was theoretically owned by the Roman state – was being farmed ever more intensely by the wealthiest cadre of Roman landowners. With the addition of ever more slave labour, these huge farms – called latifundia – were soon operating on a scale that dwarfed all the traditional local farmers, and thus left the peasantry across Roman-controlled territory without any paid work.

Therefore, to seek out a viable livelihood, or indeed to stay alive, this impoverished rural populace poured into the urban quarters of Rome. The city’s population expanded rapidly, becoming in the classical period, the first city in the world to host – if not boast – a million people. For there were three clear problems to this high-paced, unregulated and fundamentally imbalanced growth: first, there was no land in Rome for anyone to farm for their own consumption; second, and more problematically, the agricultural land around Rome was simply not sufficient to support the total populace of Rome; third, the big landowners, whose estates lay farther afield, had become more interested in higher-margin goods such as oil and wine, which meant decreased production of that most important staple, grain. In such circumstances its prices necessarily increased, far out of the reach of the unemployed urban poor. Without rapid redress, Rome was in acute danger of either starvation or riots.

Something drastic needed to be done, and in the late second century BC two brothers – Tiberius and Gaius Gracchus – made the move. They sought to speak up for the plebs – that is, the common, non-elite and typically very poor Roman citizen – by demanding that ownership of land be limited to 125 acres (in our terms). Furthermore, they asserted that all of the rest of the land conquered by the state be distributed to ‘normal’ Roman citizens among the plebs so as to allow them to return to the idealised life of sustainable rural farming. Unsurprisingly, the aristocracy detested this radical idea; although the law was passed by these iconoclastic officials (when serving as Tribunes of the Plebs), both Tiberius and Gracchus lost their lives in the chaotic fallout of such controversial policies. Nevertheless, the population of Rome continued to increase into the first century BC, and the state came to the sobering conclusion that nothing could be more dangerous than letting the city’s inhabitants go hungry and thus turn to unrest. We will return to that very real problem shortly.

First, we may round off our tour of how ancient trade operated beyond the daily markets. Not just Rome but many other larger towns and cities operated on an eight-day cycle, at the end of which were held special market days called nundinae (literally ‘ninth-days’, because the Romans counted inclusively, the day after tomorrow being ‘three days away’). On nundinae all non-trade work was paused, and no official business was conducted by the patrician elites; no political votes could be held; every school was closed. Since groceries of all kinds were on sale, customers typically purchased commerce for the eight days ahead – not unlike the ‘weekly shop’ of our own era. These market days brought local tradespeople to the city, as well as itinerant traders (circumforanei) who moved from nundinae to nundinae as they each fell on different schedules in different cities.

Trade at these and all other markets was regulated by four magistrates called the aediles. They oversaw which places could lawfully hold market days, whereas the introduction of any new such nundinae required a formal petition to be sent right up to the senate: the freedom to trade at large scale demanded state approval. The Temple of Castor, located in the Forum as mentioned earlier, contained the official standards for weights and measures. Meanwhile, collegia of tradesmen looked out for the shared interests of their particular trade, much as medieval guilds and livery companies did, or modern trade unions do. In addition to these days, and the largest events of all, there were occasional seasonal fairs, called mercatus.

While the aristocracy praised the simple business of farming, they were much sniffier about commerce. The otium (leisure) of the large landowner was set in stark contrast with the negotium (literally ‘not-leisure’, i.e. business) of tradesman. It had become a literary cliché that the sea – which allowed trade with far-flung nations – was a source of corruption, greed and immorality, and that harbours were dens of iniquity. Writing in the age of Nero (r. AD 54–68), Seneca could ask quid opus est mercaturis, ‘What need is there of commerce?’ (Consolation to Helvia 10.5). Elite Romans solemnly agreed that only foreigners or slaves should be involved in retail as merchants (mercatores). What is more, there was a legal as well as social block against their own direct involvement: a law passed in 218 BC mandated that senators and their sons were forbidden from owning trade ships, i.e. those that could carry a cargo of more than 300 amphorae. They were also forbidden from another major source of money-making: tax-farming, whereby a contract was secured with the Roman state that allowed, in exchange for the payment of a periodical rent, the right to exact taxes from a region within the empire, potentially far over and above the sum that was being paid to Rome.

Yet since the Roman, and indeed human, desire to be ever wealthier was inescapable, aristocrats avoided the social stigma of direct trade by investing in all manner of financial ventures via negotiatores (businessmen), who were often well-established figures of the equestrian (knight) class. Thus, at a polite remove from actual trade deals, elite Romans could play a major economic role by investing in, and profiting from, trade. In addition, alongside the state bankers (mensarii) and private creditors (argentarii), senators were permitted to lend money on interest, and did so on an eye-watering scale.

No less important were the logistical challenges posed by travel in the ancient world. Given the sheer size of the empire it was natural that some high-tariff products could and would be transported over huge distances. Luxury goods were exchanged over many thousands of miles: in return for Roman exports of gold and silver, ceramic, marble and glass – or for large amounts of Roman coinage – rare and expensive goods were imported from across Northern Europe, Arabia, India, and even China (albeit probably indirectly). In addition, and across the empire, an ever more diverse array of humans captured in warfare were shipped to Rome and her largest estates to be sold as slaves.

However, as Monte Testaccio amply demonstrates, long-distance travel could also occur on a massive scale for much more everyday products: grain came to the capital first from Sicily, and then from the broad breadth of North Africa. This naval route often made good economic sense, since travel by road was some 50 to 70 times more costly than that by sea and river. It was therefore cheaper to ship grain from one end of the Mediterranean to the other than to transport it by land for a mere 75 miles. Thus, as in our modern supermarkets, many of Rome’s everyday staples, such as grain, oil, wine, salted fish, pottery, and papyrus, had often travelled hundreds or thousands of miles before reaching the customer.

Yet it was not the case that all of the empire’s trade involved Rome acting as the arch-importer. For there were two important drivers for regional trade throughout the provinces. First, many aspirant people around the empire actively sought to ‘Romanise’ themselves, which led to their importing characteristic Roman goods, such as crockery, clothing and art. Second, and more pressingly, there was the need to pay the tributum (tribute, or tax bill), which often could only be done by increasing local production and trade in order to have money available. So, the distant demands of Rome could catalyse local economic activity without the direct involvement of the imperial overlord.

To what degree, then, can we speak of free trade occurring across the empire? While there were some tolls and taxes, in principle the market was open to any willing and able entrepreneur, and not just to Roman citizens. In reality these markets were a space where patronage, connections, and friendships in the no-nonsense Latin sense of the word (amicitia) played an important role in securing contracts. Nevertheless, monetary unity, low customs duties, and the efficient trading community of the two-language system (utraque lingua) of Latin in the west and Greek in the east all helped grease the wheels of trade. The market forces of supply and demand applied as expected for most commodities, and prices could respond accordingly, despite notable regional variance. However, two essential goals of the Roman state complicated matters: the need for grain in Rome (annona urbis), and for a well-fed and contented army (annona militaris).

All Romans needed a prodigious amount of grain. In the normal, non-elite Roman diet, 75 per cent of the calorific intake came from grain, another 15 per cent from oil and wine, and therefore just 10 per cent from other foodstuffs. What is more, 20 per cent to 30 per cent of Rome’s imported grain was given over to the grain dole, the system whereby it was handed out to the poor for a token low sum, or entirely for free. At its height, it is estimated that 63,000 tons of grain were handed out per annum to 150,000 eligible people. In such circumstances, controlling prices was hard: grain was for the Romans what we call a Giffen Good (after the Scottish economist Sir Robert Giffen), that is, one for which demand paradoxically rises when its price rises. The Roman state therefore sought to keep the grain price stable, since that in turn kept many other goods stable on the open market. In such an environment the trade of grain in the empire could not be free. The Egyptian supply of grain, for instance, was carefully watched once it became a Roman province in 31 BC: its sale to anywhere other than Rome was at first banned, and then closely controlled, so that the capital’s supply could never be in doubt.

In order to keep the city sufficiently stocked with grain, a total of 2,000 to 3,000 voyages were required annually. This demanded a huge merchant navy: at first, the Romans offered subsidies to shippers, or targeted tax exclusions; later, they effectively took on the financial risk for those who shipped grain all year round, especially in winter. In turn, all shipowners (navicularii) were compelled to join specific collegia so that they could be easily supervised by the state. Meanwhile, the Roman navy kept the seas clear from rival peoples or pirates, the latter of whom posed a major problem until Pompey the Great did much to subdue them in the first century BC.

Second, there was the huge size of the army, which employed half a million soldiers at its biggest extent, and thus accounted for almost three quarters of state expenditure. Fundamentally, with the army spread all around the farthest fringes of the empire, the private sector did not have the scope or resources to support them. Instead, it was necessary for the state to oversee the circulation of food, drink and other essentials to sustain the forces. The Romans built their vast network of roads: 250,000 miles in extent, of which over 50,000 miles were covered in stone. This was the infrastructure for the cursus publicus, the public distribution network that could only be used by those on official business for the state. Given the scale of their presence, it is no surprise that wherever the army was camped for prolonged periods it was seriously disruptive to local economies, in both positive and negative ways. While some local produce was bought by soldiers, much was simply yet many locals made efforts to live off the army by providing other services or support as economic parasites (lixae).

For many centuries this immense and unsinkable system was able not just to survive but thrive. But myriad factors eventually conspired to the decline of the empire: by the early third century AD, the Roman dole of grain was replaced by a more lavish one of bread, probably under Septimius Severus (r. 193-211), who also began dispensing olive oil; three generations later the Emperor Aurelian (r. 270-5) felt it necessary to add wine and pork to the dispensation. These gestures reflect the economic crisis of the century as a whole, which involved rapid debasement of currency, and hyperinflation – at times rising to 15,000 per cent. To arrest the chaos, Diocletian issued in 301 his infamous Edict of Maximum Prices, which of course failed to work at all on the ground.

The empire would never recover from these upsets: once confidence in Roman currency was lost, and once trust in the imperial regime’s ability to keep the show on the road was tested to its limits, large-scale trade gradually wound down and retreated to its primary areas of urban activity across the empire. Within a few centuries Rome herself was reduced to a sleepy backwater – a space to which agriculture could slowly return but in which stable trade would not re-emerge until the second millennium AD. But, as that multi-millionaire entrepreneur (and Stoic philosopher) Seneca wrote, quid opus est mercaturis?