(Tacitus,
Histories
4.74)
The Political Economy of Tributary Empires
Who paid for empire? Like all imperial rulers, the Romans passed the cost on to their subjects. Romans knew this. Tacitus puts this pithy summary of imperial economics into the mouth of the Roman general Cerealis, in a speech aimed at dissuading the Gallic tribes of the Treveri and Lingones from joining the rebellion of
AD
69. This was, indeed, the bottom line. By Tacitus’ day the army devoured most of what the emperors raised in taxation. Put like this, the resourcing of Roman imperialism seems very simple. Yet the mechanisms employed were phenomenally complex and in constant evolution. Roman history is, in some sense, the story of unending struggles to balance the imperial budget. Perhaps this was true for all imperial states.
A comparative perspective indicates the tight constraints within which Rome had to solve these problems. Early empires were vast redistributive systems: the key resources on which they depended were land and manpower. Metals, timber, and hard stone were also important; correspondence between the Bronze Age kings of the ancient Near East was already often preoccupied with securing these precious resources. But the basis of all ancient economies was agriculture. Every early empire was, in the final analysis, funded from the agricultural surplus. Given that empires were built on inequality and were very large, they also depended on transport infrastructure. Empires typically spent on soldiers, functionaries, and imperial courts, and none of these groups was evenly distributed among the productive landscapes they controlled. There were not many options. Food could be moved to the consumers; the consumers could go to the food; or else monetary systems could be devised which allowed states to pay in cash but required subject populations to sell surplus on the market to earn money to pay taxes, and consumers to use the market to obtain what they needed. Rome eventually used a combination of these, building roads and ports, levying taxes in kind and in cash, providing incentives for traders to bring their cargoes to the imperial capitals, and expecting provincial populations to supply armies and imperial courts on the move.
1
The Roman solution was therefore broadly similar to that employed by other early empires. Great infrastructure projects included the Grand Canal of China, begun in the fifth century
BC
and nearly 1,000 miles long by the time of its completion a millennium later; the Persian Royal Road that ran over more than 1,500 miles from Sardis to Susa; and the great Inka Road that ran 3,700 miles along the length of the Andes. Rome was especially fortunate in ruling an empire arranged around an inland sea. Moving the consumers to the food was less practical for empires than for smaller states. Early English kings could move their tiny courts around their little kingdom with relative ease, but empires required more complex systems. As a result most created imperial monetary systems with which to pay soldiers and state functionaries. Often this involved extending the uses of an earlier coinage, like the copper coins of the Qin kingdom that became the first imperial coinage of China, or Rome’s silver denarii which in the course of the late Republic gradually replaced all the other precious metal coinage of the Mediterranean world.
2
Along with imperial coinages there usually went imperial standard measures. The Athenians’ conversion of the Delian League into something like an empire was marked when the assembly issued a decree, probably in the mid-420s
BC
, requiring its allies to use Athenian
coins, Athenian weights, and Athenian measures.
3
The Achaemenid Persian Empire issued coinage and demanded some taxes be paid in coin: Hellenistic empires typically made more used of standardized monetary systems.
4
Historians sometimes call this sort of political system a tributary empire, perhaps for obvious reasons.
5
Tributary empires may be contrasted with conquest states, polities with institutions and ideologies geared to constant expansion. The Aztec political order depended on annual war, and it had state rituals that demanded constant supplies of war-captives for sacrifice. A run of years without victories would cause political collapse. When conquest states enjoy a sustained comparative advantage over their neighbours, periods of astonishingly rapid expansion might occur. Typically this involved not only rewards for the conquerors, but also means by which new members were recruited to their armies. Conquest states move like tsunamis across political landscapes. The Arab conquest that between 634 and 720 created a caliphate stretching from southern France to the Punjab, and the Inka conquest of the Andes in the century after
AD
1438, were both movements of this kind. But this kind of forward drive cannot be maintained indefinitely. All conquest states are doomed either to sudden collapse (like the empire of Attila the Hun) or else to become institutionalized as tributary empires. Achaemenid Persia provides an excellent example. The empire was created between 559 and 522 by Cyrus and his son Cambyses, who together conquered the kingdoms of the Medes, the Babylonians, and the Egyptians: but their empire nearly collapsed in civil war until Darius I took control, creating a single currency, a tax system, a provincial system, and the Royal Road. Greek and Roman writers, spellbound by the horror of civil war, present the achievement of Augustus mostly in terms of establishing civil peace.
6
But what really saved the empire from collapse was his success in stopping expansion, and consolidating it around those institutions that were already geared to the sustainable economics of a tributary empire.
Here too there were only a few fiscal options open to the rulers of tributary empires. Local rulers of various kinds could be recruited to act as agents of empire; tax farmers could be employed; or a tax-gathering bureaucracy could be created. Each method had its disadvantages. Depending on local elites meant surrendering some power over the provinces. A detailed comparison has recently been drawn between Rome’s use of local elites and the situation in the Mughal Empire which extracted tax with the help of local
zamindars
, in the process conceding them significant autonomy.
7
Tax farmers minimized the risks and costs of tax collection, guaranteeing the state a fixed income. But they notoriously had short-term
interests, and were the least sympathetic to taxpayers. The long-term disadvantages of public–private partnerships of this kind are now very familiar to us: tributary empires also had to run the risk of revolts and protests stirred up by profiteering. A bureaucracy gave emperors much more control, but it came at a significantly higher cost, one that in the end would have to be recouped from the taxpayers.
The broad path of Rome’s own journey through these tangled waters is simply stated. Roman expansion in Italy conforms closely to the ideal type of a conquest state. But already within the second century
BC
elements of more stable revenue extraction appear. Indemnities from defeated powers were replaced over that century by regular income, as former Hellenistic kingdoms were absorbed and other territory was won in the west. At first Rome depended on tax farmers: for a state already making the widespread use of public contracts that Polybius observed this was natural. But tax farming was impractical in some regions—notably Spain—and the appalling behaviour of those who held the contract to collect Roman taxes in Asia was widely blamed for Greek support for Mithridates. Caesar entrusted the collection of land tax to the local elites of Asian cities, and that system became widespread during the early first century
AD
except in Italy, which was exempt, and Egypt where the bureaucracy used by the Ptolemies was preserved, and perhaps some frontier zones where the military acted as different kinds of bureaucrats. The early imperial system remained, however, exceptionally complex and tax farming continued to be used for many indirect taxes.
8
The Augustan system had most consistency at the very highest level. Further down, there was little desire to tinker with systems that worked well enough, and only a few attempts to make improvements can be documented. All this changed in the crisis of the third century. The empire needed greater revenue at a time when the economy was for one reason or another weaker, and when local aristocracies were under unprecedented pressure. The result was that as part of the imperial recovery a new system emerged, with new taxes, a new coinage, and a centralized bureaucracy that lasted into the Byzantine Middle Ages.
Good Times and Bad Times
Fiscal systems can be seen as governmental responses to the economic activities of their subjects. Ideally they extract as much as possible without
harming that activity. As Tiberius is said to have put it: ‘I want my sheep shorn, not flayed.’ The historical ecology of the Mediterranean basin and its hinterlands has been described already.
9
The agrarian regimes of classical antiquity were essentially stable. Roman rule brought a few new farming techniques and a few new crops into some regions, but there was no revolutionary change. That ‘normal’ background had some built-in short-term instability, especially in the Mediterranean part of the empire where food crises were not unusual.
10
More generally the ancient Mediterranean was characterized by highly localized cycles of boom and bust that drove peasant cultivators into strategies of crop-diversification, storage, and exchange.
11
Growth, where it took place, was the result of intensification. Where landowners had the funds and the desire we can observe them draining and irrigating; planting vines, olive trees, and gardens that would be more profitable than other crops; experimenting with new varieties of trees, with selective livestock breeding; improving the value of their estates by opening up clay-pits, building kilns and olive presses; constructing mill and storage facilities; and improving the transport facilities they used to get their surplus to market. Broadly speaking, the poor feared risk, the rich sought profit, but both pursued their ends by essentially traditional means.
Yet long-term trends did emerge from this activity, trends with which the tributary empire had to deal. Work progresses apace on filling out the details of these trends, and especially on quantifying them.
12
Underwater archaeology has shown how the numbers of shipwrecks rose to a peak in the late Republican period, suggesting this was the period of greatest long-distance trade in the ancient Mediterranean.
13
Over the same period Italian products, especially wine and ceramic tableware, are found all over the Mediterranean world, and beyond it too. From the early first century
AD
this evidence diminishes in volume. But there are indications of growth in the provinces, including the production of olive oil for export in North Africa and southern Spain, and the production of wine for local consumption in areas as varied as central France, the environs of Rome, and Egypt. Trade, in other words, boomed first, followed by the capacity to produce the same goods locally.
14
New evidence for increased levels of mining and metal production has come from ice cores drilled through the Greenland ice cap. To judge from the levels of atmospheric lead and copper pollution attested there, the production of metals reached a peak in the early Roman Empire not repeated before the Industrial Revolution.
15
For the most part, these changes were demand led. For example, one major stimulus to change was the spread of new styles of consumption across the empire, styles modelled on those of the Italian elites. Oil, wine, fish-sauces, textiles, bronzes, ornaments were all in demand among their provincial counterparts. Changes in consumption did not affect commodities alone. Teachers and potters and wall painters found employment in the provinces. Italian architects, engineers, and craftsmen were already at work on public buildings in the western provinces in the early first century
AD
.
16
Once these skills had been taught to locals, quarries had been opened up, tile production had begun, and new carpentry techniques and design features were disseminated, we begin to see the transformation of domestic architecture, first in the cities and then in the countryside. Even more sophisticated engineering skills were needed to build aqueducts that powered monumental fountains and bathhouses, signs of new aesthetic and cosmetic sensibilities. All this was expensive, but if some of Rome’s subjects were exploited more to pay for it, others might make money satisfying these new tastes.
17
The greatest change in lifestyle in many parts of the empire was the growth of cities. The number of cities, their density, and the population of the larger centres grew all over the empire. Regions with only villages before Rome—inland Gaul and Spain, central Anatolia, parts of Egypt and the Balkans—experienced the greatest growth. In a few areas, such as the Nile Valley, central Italy, and coastal Asia Minor, the proportion of non-producers who had to purchase their food crept up to as much as 30 per cent of the population. A large part of this growth was the consequence of the emergence of a small number of enormous cities at the top of the settlement hierarchy. The population of Rome reached around one million, and maybe ten other cities crossed the 100,000 mark. The urban system itself was changing, and in some areas small cities grew smaller as the larger ones swelled in size.
18
But by most estimates the total urban population of the empire increased to a maximum around
AD
200.
19
Add to this the creation of a standing army that fluctuated between a quarter and half a million men, and it is clear where the new demand was coming from.