Ancient Roman economy, trade and commerce Research Papers (original) (raw)

This paper examines evidence, both documentary and archaeological, for state interest in Indo-Mediterranean trade via the Red Sea, focusing on the creation of infrastructure to facilitate trade, measures taken to protect trade and traders, and the extent of the state’s interest in the trade principally as a result of customs dues, which it is argued formed a significant and hitherto under-appreciated source of income for the Roman state.

The development of Indo-Mediterranean trade in large volumes via the Red Sea route in the Augustan period was the result of a combination of at least three main factors: (1) the creation of overland routes between the Nile and Red Sea, obviating the need for ships to beat up to the Gulf of Suez against strong northerly winds; (2) the discovery of the use of the monsoon winds, enabling a more direct passage to and from India; and (3) the incorporation of Egypt into the Roman Empire after Actium. The flourishing of this trade for several centuries under the Roman Empire relied on effective protection of these routes.

The first piece of this jigsaw was put in place under Ptolemy II Philadelphus, with the creation of regular overland routes across the Eastern Desert between the Nile and the Red Sea. Crucial to these routes were the watering points or hydreumata created along them, which cannot have functioned without the use of the new saqiyya technology enabling the lifting of water from deep wells in quantities sufficient to feed desert caravans. The invention of the saqiyya machine has been placed by Lewis (1997) in the window 280-220 BC, and may probably be narrowed further to the earlier part of this period. Right-angled gearing was sufficiently well developed by c. 240 BC for Archimedes to use it in his hodometer cart - and probably also was used in automata vehicles in the Grand Procession of Ptolemy Philadelphus in 270 BC. In other words, the components of the technology were there during the reign of Ptolemy Philadelphus and it is difficult to believe that it was not used on this desert route. Possibly an important motivation for the opening of the overland route between the Nile and the Red Sea was to enable the supply of war elephants from the Sudan, but the routes clearly facilitated commercial traffic with the Red Sea and the souther Arabian peninsula.

With the development of trade with India via the Red Sea, following the discovery of the monsoon winds and the incorporation of Egypt into the large market of the Empire, the Roman system would have intensified the infrastructure on the Ptolemaic route to support increased traffic, with construction of new hydreumata attested by inscriptions. Pliny mentions some road stations; others were added in 76/77by the prefect of Egypt Julius Ursus (O.Ber.II.120). The kykleutikon salary of several 1st- and 2nd-c AD ostraca was for operating this kind of saqqiya device. Forts were also constructed, and caravans were provided with armed escorts for protection against the desert nomads. Although the state’s interest was also motivated by the need to transport of granite and marble from the desert quarries, and of gold from the mines there, there was clearly a strong interest in sustaining these roads as trade routes.

This idea is supported by an examination of Trajanic policy in the region, which included the construction of the Via Nova from Aila to Bosra linking the northern Red Sea with southern Syria; the dredging and rehabilitation of the Clysma canal, and the stationing of a fleet in the Red Sea. Under Hadrian a road linking the ports of the western Red Sea coast facilitated regional communications and supplies between these increasingly important ports. In the mid second century a detatchment of troops (and ships) was stationed on the Farasan islands in the southern Red Sea, well to the south of any Roman land frontier. Their purpose must have been principally to protect trade shipping entering or leaving the Red Sea from piracy off the coast of the Arabian peninsula.

Why did the Roman state go to such lengths to invest in the physical infrastructure for the Red Sea routes, and protection services along them? The answer seems to lie principally in the customs revenue that the state derived from Indo-Mediterranean trade. Customs tariffs across the empire’s frontiers were, at least on the eastern frontiers where we have direct evidence, set at 25% until some time in the early third century, and this may have been the case universally. Strabo, writing about why Augustus did not bother to invade Britain, stresses the high revenue derived from customs dues on cross-Channel trade, which exceed the likely revenue from tribute exacted under direct rule, once the costs of enforcing that rule are deducted (Strabo, Geography, 2.5.8 and 4.5.3). The second-century Muziris papyrus values the (part-)cargo of the ship Hermapollon, in from Muziris, at nearly HS 7 million after deduction of tax, implying that the state received some HS 2.2 million from this one cargo alone. If there were only 100 such cargoes per year (a century earlier, Strabo speaks of 120 ships per year leaving Myos Hormos for India), the customs revenues from the imports alone would amount to one-third of Duncan-Jones’ estimate for the military budget of the Empire. To this must be added the export customs dues, and also the customs dues on onwards transport of much of these goods to other provinces (usually at 2.5%). It looks as if the total state revenue for the empire may have been significantly underestimated by not taking due account of the revenues from trade, especially Indo-Mediterranean trade. This in turn makes it much easier to understand the state’s ability to fund large-scale civic building projects to a level not matched again until the rise of nation states in 19th-century Europe (see debate between Scheidel and Wilson in JRA 2009).

But there were other reasons too for the state’s interest in supporting and sustaining this trade. In his rescript to the Senate in AD 22, Tiberius refused the Senate’s request to reiterate the sumptuary laws, citing as one of several reasons the fact that the real concern to the state was not controlling table luxuries, but supplying Rome with grain; much comes from Egypt, which is also the source of many luxury goods which provide profit for the grain traders (Tacitus, Annals 3.52-55). In other words, facilitating the eastern luxury trade was in indirect way of ensuring the grain supply to Rome by incentivising the participation of private shippers. The anecdote about Augustus and the Alexandrian shippers at Puteoli (Suetonius) may be seen in a similar light.

Moreover, Alan Bowman has recently argued that the imperial house was directly involved in the trade between Egypt and India (Bowman 2010). Eivind Seeland’s forthcoming analysis of donations to Churches in Rome of eastern spices and incense from estates in Egypt traces some of these back to imperial domains (Seeland forthcoming).

But some time between AD 174 and 227, the quarter-tax on external trade was reduced to a one-eighth tax (12.5%), the octava. If the eastern trade was so important to the Roman state, why halve the customs dues, especially at a time of intense fiscal pressure? The most reasonable explanation seems to be that the reduction was an acknowledgement by the state of its inability to maintain previous levels of protection for shipping and caravans, and this was a measure intended to compensate traders for increased transaction costs along these routes as a result. We hear of Blemmye raids on the Eastern Desert in the fourth and fifth centuries, and the shift in late antiquity towards more northerly ports in the Red Sea may also be connected with the increasing instability of the desert routes