Persian Trade and Economy: From the Royal Road to the Silk Road

A small clay tablet, roughly 4 by 5 cm, recovered by the Oriental Institute in the 1930s from the fortification walls of Persepolis, records a routine transaction. The hand is Elamite, the date is the seventh year of Darius I — 515 BCE — and the entry notes the issue of 110 marriš of barley to a group of twenty-eight workers. The transaction is one of perhaps 15,000 such tablets in the Persepolis Fortification archive, mostly published since the 1960s by Richard Hallock and his successors, and reworked more recently by Matthew Stolper, Wouter Henkelman, and Mark Garrison. The point of opening with this tablet is that the Achaemenid economy is known to us, in its particulars, in a way that no other ancient Near Eastern economy is. The tablets are not majestic. They are accounts of rations issued, of workers paid, of commodities moving in and out of the royal storehouse at the heart of Persis. But in aggregate, and combined with the Babylonian archive of the Murašû firm, the Jewish military colony at Elephantine, and the great tribute list of Herodotus (3.89–97), they let us write a more or less plausible economic history of the Achaemenid state — not as a sketch, but as a working model.

The same cannot yet be said of the Parthian economy, and only in part of the Sasanian. The argument of this article is that the Achaemenid state set the template, that the Parthian and Sasanian states adapted and extended it, and that the long commercial tradition of the Iranian world is intelligible only when the three are read together. Pierre Briant’s From Cyrus to Alexander (2002) is the indispensable Achaemenid synthesis; Touraj Daryaee’s edited volume Economy of the Sasanian Persia (2013) is the closest Sasanian equivalent; D. T. Potts’s The Arabian Gulf in Antiquity (1990) and The Archaeology of the Arabian Gulf (2012) are the standard references for the Gulf trade. For the longue durée I have also relied on Richard Bulliett, The Camel and the Wheel (1975), and André Wink, Al-Hind: The Making of the Indo-Islamic World (3 vols., 1990–2004).

A geographic advantage that did the work for them

The Iranian plateau sits astride the narrow waist of Eurasia, where the overland routes from Mesopotamia to India and from the Mediterranean to Central Asia converge. This is the geographic gift that none of the three Persian empires had to design and that none of them could avoid exploiting. Every caravan that travelled between China and the Mediterranean, every ship that sailed between India and the Red Sea, and every merchant who moved between Egypt and the Indus was, at some point, doing business in Persian-controlled territory.

Three great arteries radiated from Iran. The first was the Royal Road of the Achaemenids, the 2,700-kilometre highway from Susa to Sardis, consolidated by Darius I around 510 BCE. The second was the Silk Road, the network of caravan routes that linked China to the Mediterranean and that, from the second century BCE to the fourteenth century CE, ran through Parthian and Sasanian territory. The third was the maritime trade of the Persian Gulf, which connected the cities of southern Iran to India, East Africa, and the Red Sea, and which made the ports of Siraf, Hormuz, and Basra among the wealthiest in the medieval world.

The three arteries were linked. A Sasanian silver drachm minted at Merv could travel by caravan to Bukhara, by river to the Aral, by caravan again to the Ili, and by camel to Chang’an; or it could travel down the Persian Gulf to the Indus delta, by sea to the Malabar coast, and from there overland to the Tamil ports. A Chinese silk could enter the Persian economy through a Parthian intermediary at Merv and exit through a Sasanian port at Siraf bound for Byzantium. The system worked because the Persian empires, for most of their reigns, controlled the chokepoints and because they were, on the whole, less interested in monopoly than in taxing what already moved.

The Achaemenid fiscal system

Darius I, who reigned from 522 to 486 BCE, was the principal architect of the Achaemenid economy. He reorganised the empire into twenty satrapies, each assessed a fixed tribute, and introduced a system of royal inspection by the “King’s Eyes and Ears” that discouraged extortion by the satraps. He reformed the currency, issuing the daric, a gold coin of about 8.4 grams, and the siglos, a silver coin of about 5.4 grams, on a weight standard derived from Lydian practice. The famous Lydo-Miletian electrum coinage of Croesus and his predecessors is the immediate ancestor, and the Lydian mining and minting infrastructure, inherited after 547 BCE, gave Darius the metal he needed.

The tribute system, as recorded by Herodotus 3.89–97, divided the empire into twenty satrapies, each assigned a tribute in Babylonian talents of silver, in gold darics, or in kind. The richest paid the most: Babylonia 1,000 talents of silver per year, Egypt 700, the Indian satrapy 360 (in gold dust). The total, on Herodotus’ figures, was about 14,560 talents of silver per year, plus an additional amount in gold and kind. Briant, followed by most modern historians, treats the Herodotus figure as plausible on the order of magnitude, perhaps a third of the actual total. The tribute was collected by royal financial officers, not by the satrap, which limited embezzlement, and was stored in regional treasuries that could be drawn on by the King of Kings.

But the tribute was only one stream. The other was the royal economy — the system of great estates, granaries, and workshops documented by the Persepolis Fortification Tablets. Stolper’s work on the Murašû archive of Nippur (1985) and Henkelman’s work on the Persepolis Fortification Tablets (2008, 2010) have together transformed the field. The state controlled vast quantities of grain, wine, beer, and small livestock, distributed to a labour force of perhaps 15,000 people at any one time. The workers were paid in rations and a small cash supplement, and the entire system was, in Stolper’s reading, more like a redistributive temple economy in the Mesopotamian style than a market economy in the modern sense. The two systems coexisted: alongside the redistributive royal economy there were private estates, private merchants, and private money-lenders (the Murašû firm at Nippur was exactly this — a private Babylonian entrepreneurial family that flourished under Achaemenid rule by lending to other Babylonians and by managing crown-leased estates).

The introduction of the gold daric and the silver siglos gave the Achaemenid economy a monetary backbone that complemented the older system of bullion and tribute in kind. The two together provided a flexible medium of exchange that facilitated long-distance trade. The daric circulated widely across the empire and beyond, and remained stable in weight and fineness for more than a century. Xenophon (Anabasis 1.5.6) and Herodotus both treat the daric as the standard payment of mercenaries, and the Achaemenid ability to pay troops in sound coin was a major strategic asset.

The Royal Road and imperial logistics

The Royal Road, built and extended under Darius I around 510 BCE, was a logistical achievement of the first order. The most famous section, from Susa to Sardis, was about 2,700 kilometres long and had 111 royal stations. Herodotus (5.52–54) reports that a courier, using a relay of fresh horses at each station, could cross the route in seven days, while a single traveller might take ninety. The road was patrolled by royal garrisons, served by a state courier service, and dotted with inns and way-stations. It allowed the rapid movement of royal messages, the deployment of troops, and the safe passage of merchants. Tuplin’s work on the Achaemenid road and station system (in Xenophon and his World, 2004) is the closest thing to a technical study; the road is treated in the cluster article on the Royal Road in more detail.

The genius of the system was not the road itself — older caravan paths had carried traffic between Mesopotamia and the Mediterranean for millennia — but the integration. Achaemenid achievement was to combine the older routes into a single coordinated system, with standardised stations, a regular courier service, and imperial protection. The Royal Road became the model for the imperial road systems of the Hellenistic, Roman, Parthian, and Sasanian empires; the great karez (qanat) and caravanserai networks of later Islamic Iran were, in part, descendants of the Achaemenid system.

Parthian and Hellenistic commerce

The Achaemenid empire fell to Alexander in 330 BCE, and the Hellenistic kingdoms that followed — Seleucid, Ptolemaic, Antigonid — inherited the eastern portions of the Persian commercial system in a form modified by Macedonian practice. The Seleucid level of the Persepolis Fortification Tablets, the Greek documents of the Murašû archive, and the Babylonian astronomical diaries preserve a picture of a continuing commercial world, in which Greek and Mesopotamian mercantile practices coexisted. The level of monetisation actually rose in the Hellenistic period, and silver coinage in particular became more abundant.

The Parthian state, founded by the Arsacid dynasty in the mid-third century BCE, was a successor of the Seleucids in the east and a successor of the Achaemenids in Iran proper. The Parthian economy was based on the transit trade of the Silk Road, the agricultural wealth of the Iranian plateau and Mesopotamia, and the silver mines of the Zagros. The Parthian silver drachm, a Greek-style coin bearing the image of the king on the obverse and an archer on the reverse, was struck in enormous quantities and circulated from the Mediterranean to the Hindu Kush. Parthian merchants, often operating through Greek-speaking and Aramaic-speaking middlemen, established communities at every major node of the Silk Road.

The Chinese envoy Zhang Qian, sent west by the Han emperor Wu in 139 BCE, returned in 126 BCE with the first reliable Chinese account of the Iranian world. The Chinese Shiji of Sima Qian (completed c. 94 BCE) reports that the merchants of Daxia (Bactria) traded Chinese silks and Iranian lapis by caravan across the Pamirs, and that the Parthian state — which Sima calls Anxi — was the great western emporium. The Chinese envoy Gan Ying, sent in 97 CE to seek an alliance with the Roman Empire, reached the Parthian court at Hecatompylos and was persuaded by the Parthians not to continue westward. Whether this was a deliberate Parthian policy to keep the two ends of Eurasia from making direct contact, or simply a calculation that an allied Roman-Parthian frontier was not in Parthian interests, has been debated. The point is that the Parthians were, as Peter Frankopan puts it, in the middle of everything, and they were conscious of it.

Pliny the Elder’s figure of 50 million sesterces a year flowing from Rome to the East in the early first century CE is widely regarded as an exaggeration, but the order of magnitude — a substantial Roman deficit with the Parthian and Indian worlds — is accepted. Ctesiphon, the Parthian capital on the Tigris near modern Baghdad, was the commercial heart of the empire. The city, together with its Greek twin Seleucia on the opposite bank, was among the largest in the world, and its markets, banks, and warehouses handled the bulk of the east-west trade.

The Sasanian economy

The Sasanian Empire was the wealthiest state of late antiquity. Its economy was based on the agricultural productivity of the Iranian plateau and Mesopotamia, the control of the Silk Road, the silver mines of the Zagros, and the maritime trade of the Persian Gulf. Under Khosrow I Anushirvan (r. 531–579), the Sasanian state reached a level of administrative sophistication, fiscal reform, and economic integration comparable to the best of the Roman and Tang empires.

The Sasanian silver drachm, struck at mints in Ctesiphon, Rayy, Isfahan, Bishapur, Merv, and many other cities, was the principal coin of the late antique east. Its weight, about 4 grams, was derived from the Roman denarius, and it circulated freely from the Mediterranean to Central Asia. The Sasanian kings also issued gold dinars, though in smaller quantities. Daryaee, in Sasanian Persia (2009), argues that the consistency of the Sasanian silver standard for more than four centuries is the strongest single piece of evidence for the administrative depth of the Sasanian state.

Sasanian silks, with their hunting and roundel designs, were exported across Eurasia. The famous silkworm-smuggling episode of c. 552 CE, attributed to monks acting on the orders of Justinian I, is itself evidence that the Sasanian regulation of silk production was not an absolute monopoly — only a sufficiently tight one that the Byzantines considered smuggling worthwhile. Sasanian silver plate, much of it produced in the royal workshops of Bishapur and Ctesiphon, has been found in tombs from the Altai to the Hebrides and is among the most important bodies of late antique metalwork; the standard study is Prudence Harper’s Silver Vessels of the Sasanian Period (1981), and the more recent survey by Blinkenberg-Greshnykh.

The Sasanian tax system, reformed by Khosrow I, divided the empire into administrative districts and assessed a fixed tax in silver or in kind, paid by landowners and peasants. The system was rigorous, well documented, and applied across the empire. The Sasanian state invested heavily in irrigation, including the construction and maintenance of qanats (underground water channels), the repair of bridges, and the digging of canals. The agricultural productivity of Sasanian Mesopotamia, Khuzistan, Fars, and Azerbaijan was the foundation of imperial wealth. The Sasanian land tax, the kharaj, and the poll tax, the jizya, were continued by the early Islamic caliphs, with modifications.

The Persian Gulf and maritime trade

The maritime trade of the Persian Gulf was a major component of the Persian economy from the Achaemenid period onwards. The Achaemenid state absorbed the Phoenician and Ionian fleets, dominated the gulf, and used it to project power into India and the Indus Valley. Darius’s Red Sea canal, which linked the Nile to the Red Sea, was one of the great engineering works of the ancient world, and the Sasanian state, with its ports at Siraf, Hormuz, and Basra, controlled the sea lanes that connected Mesopotamia to India, East Africa, and the Red Sea.

The earliest attested gulf trade is that of Dilmun (modern Bahrain), whose merchants appear in Sumerian texts of the third millennium BCE as middlemen between Mesopotamia and the Indus. Dilmun, Gerrha in eastern Arabia, and the ports of southern Iran handled the trade in copper, dates, pearls, textiles, and precious stones. Under the Sasanians, the gulf ports reached an unprecedented level of prosperity. The port of Siraf, on the coast of Fars, was at its ninth- and tenth-century peak one of the largest ports of the Persian Gulf; the population estimates range widely, from 30,000 to 100,000, and the published archaeology (Whitehouse, Siraf project of the 1970s) is the standard reference. The goods handled included Indian textiles, spices, and jewels; Chinese silks and porcelain; African ivory, gold, and slaves; and the products of southern Iran, including dates, silver, and carpets.

Potts, in The Arabian Gulf in Antiquity (1990), argues that the gulf trade is best read as a series of overlapping regional networks rather than a single trans-oceanic system. The Indian merchants, the Arab dhow crews, the Sasanian administrators, and the African gold-traders of the upper Nile all operated in their own circuits, meeting at specific entrepôts — Aden, Hormuz, Siraf, Cambay — and exchanging goods in the kind of polyglot marketplace that the early Islamic geographers describe in such loving detail.

The early Islamic transformation

The Arab conquest of the Sasanian Empire in 651 CE transformed the commercial landscape of the Middle East. The caliphs of the Umayyad and Abbasid dynasties made Arabic the language of administration and the gold dinar the standard gold coin, but they relied heavily on Persian bureaucratic and commercial expertise, and the great cities of the Iranian world — Isfahan, Shiraz, Nishapur, Merv, Bukhara — remained commercial centres of the first rank. The Pahlavi-period academic study of this era owes much to the Cambridge History of Iran, vol. 4 (ed. Frye, 1975) and vol. 6 (ed. Jackson and Lockhart, 1986).

Persian merchants in the Islamic world established communities from al-Andalus to China. The Rādhānite Jewish merchants of the early Islamic centuries, whose trans-Eurasian trade networks are described by Ibn Khordadbeh in the Kitāb al-Masālik w’al-Mamālik (c. 846 CE), operated across the Islamic and Christian worlds from centres as far west as the Rhineland. The Samanid and Buyid courts patronised trade with the Volga Bulgars, the Rus, and the Turkic peoples of the steppe. The great Seljuk vizier Nizam al-Mulk, in his Siyāsatnāma (Book of Government, written 1091–1092), emphasised the importance of trade, justice, and security for the prosperity of the realm. The Mongol conquests of the thirteenth century, while destructive, also opened new trade routes and brought the Persian world into closer contact with China.

The Persian carpet became, in the Islamic period, a major export. The Seljuk and post-Seljuk courts of Iran patronised workshops that produced some of the most elaborate carpets of the medieval world, and the great Safavid court of Shah ʿAbbas I at Isfahan developed a carpet industry that exported to Europe in unprecedented quantities. The Mamluk, Ottoman, and Mughal courts all emulated Persian textile, ceramic, and architectural fashions.

What the merchants did, and what we don’t know

Persian merchants, working within the framework of Islamic law, developed sophisticated financial instruments. The sakk (cheque) and suftaja (bill of exchange) were developed in the medieval Islamic world, with Persian merchants playing a leading role, alongside the Arabic-tradition mudāraba (sleeping partnership) and bayʿ al-salam (forward sale) contracts. The precise weighting of the Persian contribution is debated; Abraham Udovitch’s Partnership and Profit in Medieval Islam (1970) and Bankers without Banks (in Studies in the Economic History of the Middle East, 1978) are the standard treatments, and the relevant Encyclopaedia of Islam articles are essential.

The medieval Islamic banking system, with its money-changers, deposit banks, and letter-of-credit networks, owed a substantial debt to Persian commercial practice, though it cannot be reduced to a single origin. The qirad (limited partnership) and the mudāraba are Arabic legal forms; the istisna’ (manufacturing contract) is a broader Islamic development. The history is best read in Udovitch, with the caveat that the documentary record is heavily weighted toward the Genizah documents of the Cairo Jewish community, which gives a particular view of the trade.

The bazaar of the Persian-speaking world was, and remains, the principal commercial institution of the cities. The bazaar was typically a covered network of streets, alleys, and courtyards, with shops, workshops, and warehouses grouped by trade. The great bazaars of the Persian world — the Bāzār-e Bozorg of Tabriz, the Qeysariyya of Isfahan, the Bāzār-e Vakīl of Shiraz — were major commercial centres and major centres of social life. The bazaar contained not only shops and workshops but also mosques, madrasas, bath-houses, and caravanserais. It was, in effect, the principal public space of the Persian-speaking city.

The standard of value

Persian coinage, from the daric of Darius I to the silver qiran of the Qajar shahs, set the monetary standard for the Near East for two and a half millennia. The Achaemenid daric, with its purity of gold and consistent weight, was famous throughout the ancient world; Herodotus reports that the Persians paid their soldiers and officials in darics. The Sasanian drachm was the principal silver currency of the late antique east, and the dirham of the Islamic caliphs, modelled on the Sasanian coin, became the standard of value in the medieval Islamic world. The Safavid and Qajar qiran continued the tradition. The standard reference is John Curtis’s chapter in Coins of the Ancient World (2009) and the relevant Encyclopaedia Iranica articles on Persian coinage.

The continuity is striking, and the temptation is to read it as evidence of an unchanging Persian commercial genius. The temptation should be resisted. What persisted was the geographic position, the urban network, and the institutional capacity to tax transit trade. The specific commodities, the specific merchants, and the specific financial instruments changed radically across the period. The Sasanian drachm and the Qajar qiran are linked by no continuous line of mint practice; they share a monetary standard and a regional role. The Achaemenid daric and the Achaemenid barley-ration tablet are linked by no continuous line of economic practice; they share an imperial system and a territory. To read the long Persian commercial tradition as a single, coherent story is a useful working hypothesis. It is also, on closer inspection, a story of constant reinvention.

What we do not know is, in some respects, more interesting than what we do. We do not have a continuous series of Parthian administrative documents comparable to the Persepolis Fortification Tablets; the Parthian economy is reconstructed from coins, from Greek and Latin authors, from a few ostraca from Nisa, and from archaeology. We do not have a Sasanian archive comparable to the Murašû archive; the Sasanian economy is reconstructed from coins, from Pahlavi literature, from Roman and Byzantine sources, and from archaeology. The Persepolis archive is a gift. It is also a single window. We should be careful not to generalise from it to the whole of the Achaemenid economy, and we should be especially careful not to generalise from it to the Parthian or Sasanian.

Brief notes on Persia and the wider world

The Persian empires played a major role in the world spice trade. Indian spices — pepper, cinnamon, cardamom, cloves, nutmeg — were imported through the Persian Gulf and re-exported to the Mediterranean and the Middle East. The Roman Empire was a major consumer, and the trade in spices was a major element of Roman-Indian commerce. The Sasanian kings derived substantial revenue from the customs duties on the spice trade. The medieval Islamic spice trade continued the patterns of the Sasanian period, and the cities of Basra, Baghdad, Isfahan, and Shiraz were major centres of the trade. The spice trade declined in the early modern period, as the Portuguese and the Dutch established direct sea routes to India around the Cape of Good Hope, but the memory of the medieval spice trade lived on in the literature and the art of the Persian-speaking world.

The slave trade was a component of the Persian economy from antiquity to the modern period, though its scale is debated. Slaves were drawn from a wide range of sources, including East Africa, the Caucasus, Central Asia, India, and the Slavic-speaking lands of eastern Europe. The Sasanian state used slaves in domestic and administrative roles; the Sasanian court maintained substantial slave households. The Islamic period saw a continuation and expansion of the Persian slave trade, in which Persian-speaking merchants participated. The Ghaznavid and especially the Seljuk dynasties made extensive use of Turkish slave-soldiers, the mamluks, a practice that culminated in the Mamluk Sultanate of Egypt (1250–1517) and the Delhi Sultanate’s Turko-Afghan ruling class.

The crafts of the Persian world — in particular the textile, metalwork, ceramics, and carpet industries — were organised into guilds, the asnaf. The guild was typically organised by trade, with separate guilds for the weavers, the dyers, the metalworkers, the carpenters, the jewellers, and the other crafts. The guild maintained its own workshops, trained its own apprentices, regulated its own production, and protected its own members. The guilds of the major cities — Isfahan, Tabriz, Shiraz, Bukhara — were major political forces, and they often played a decisive role in the political life of the city. The legacy of the guilds lived on in the continuing tradition of the bazaar and the asnaf in the modern Islamic world.