The Sasanian Empire: The Last Great Persian Empire

A working philologist’s confession. The Sasanian Empire is the period of Iranian history where the primary sources reward close reading most generously — and punish it most harshly. The Pahlavi corpus is, in Mary Boyce’s phrase, “scanty, late, and often corrupt,” and D. N. MacKenzie’s Concise Pahlavi Dictionary (1971) remains the indispensable instrument for moving through it. Read the Bundahishn alongside Tabari’s Tarikh, read the Kar-namag i Ardashir alongside the ŠKZ inscription at the Ka’ba-ye Zartosht, and the picture comes into focus slowly, sometimes in places the literary sources do not advertise. The Sasanian achievement was considerable: a centralised monarchy, four centuries of war with Rome, a Zoroastrian church that codified its own canon, a coinage that held 90 percent silver purity across centuries, a textile design that travelled the Eurasian steppe, and a state template that the caliphs of Islam would adopt within a generation. The Pahlavi evidence, fragmentary as it is, is what makes that achievement legible.

The principal modern syntheses in English are Touraj Daryaee’s Sasanian Persia: The Rise and Fall of an Empire (2009), Parvaneh Pourshariati’s Decline and Fall of the Sasanian Empire (2008), and the Sasanian volumes of the Cambridge History of Iran. The Sasanian inscriptions are collected in Martin Sprengling’s Third Century Iran (1953) and, more recently, in the Corpus Inscriptionum Iranicarum. For the Roman and Byzantine side, Ammianus Marcellinus, Procopius, and the later Greek chroniclers are translated in the Loeb series; for the Arabic and Persian tradition, the Tarikh of Tabari (d. 923) is indispensable. The next two thousand words are an attempt to make sense of what they say.

Persis and the Sasanian revolution

The Sasanian state did not come out of nowhere. Its base was Persis, the highland province of Fars that had been the Achaemenid homeland and that the Arsacid empire had governed through a series of client kings. The dynasty’s eponymous ancestor Sasan is barely historical; the Pahlavi Kar-namag i Ardashir describes him as a priest or minor notable in the service of the fire temple of Anahita at Istakhr. His son Papak (or Babak) is more secure; an inscription of his survives, and the local dynasty he founded at Istakhr in the late second or early third century is a matter of record. Papak’s son Ardashir was the dynamic figure. By about 205 CE he had displaced the local Arsacid governor and begun to absorb the surrounding principalities. By 220 CE he controlled Elymais and was raiding into Roman Mesopotamia. By 224 CE he had taken the title shahanshah.

Pourshariati’s thesis, which has dominated Sasanian studies since 2008, holds that the Sasanian revolution was not a simple Achaemenid restoration but a coalition of the Persid, Abnuhi, Ispahbudhan, Mihran, Zik, Spandiyadh, and Karen noble houses, with the Sasanian house as its leading family. The old Parthian clans did not disappear under Ardashir; they were absorbed and re-deployed. This complicates the older nationalist narrative, in which the Sasanians simply “recovered” the Achaemenid past. My own view is that Pourshariati is largely right on the political structure, but the religious programme — the aggressive Zoroastrianisation of the state under Shapur I and his successors — was genuinely new and is not reducible to aristocratic realignment.

What is not in dispute is the speed and brutality of the consolidation. Ardashir’s son Shapur I extended the new state into Roman Mesopotamia, captured the emperor Valerian at Edessa in 260 CE, and issued the trilingual inscription at the Ka’ba-ye Zartosht at Naqsh-e Rostam (ŠKZ, the “Res Gestae Divi Saporis”) that is the single most important Sasanian document. The inscription is propagandistic, but it gives the dynasty’s own account of its early campaigns, and it is the only Sasanian royal inscription in which the king speaks in the first person at length.

Government

The Sasanian state was the most centralised Iranian polity before the Pahlavi monarchy of the twentieth century, though it was not the absolute monarchy of the Shahnameh tradition. At its head stood the shahanshah, whose person was sacred and whose authority was, in theory, derived from the divine farr. In Pahlavi political theology, the farr was a substance as much as a metaphor, and the loss of it was a sign of dynastic failure. In practice, the shahanshah ruled with the consent, and sometimes against the resistance, of the great noble families and the Zoroastrian priesthood.

The court was centred on Ctesiphon, the great Mesopotamian city on the Tigris that the Sasanians inherited from the Parthians and rebuilt on a larger scale. The imperial chancery, the dabīrbed, produced documents in Middle Persian, Greek, Parthian, and Aramaic; the surviving Sasanian documents are mostly on parchment and ostraca, with the famous Antinoopolis papyri (c. 7th century) as a notable exception. Below the dabīrbed stood a hierarchy of officials: the wuzurg framadar, the aspbed, the moabadan moabad, and the hamarakar. Most of these titles survived into early Islamic administration; the dabīr of the caliphal chancery, the wazir of the Abbasid vizierate, the sipahsalar of the military command — all are calques of Sasanian originals.

The empire was divided into a number of provinces whose exact count is debated. Ammianus Marcellinus and the later Arabic geographers give varying numbers; the surviving Pahlavi sources speak of four cardinal provinces (kust) and a number of subordinate ones. Each province was governed by a shahrab (often translated “satrap”) who combined civil, military, and judicial functions. The frontier provinces along the Roman and later Byzantine border were governed by marzbans, whose title is the ancestor of the medieval Latin marchio (marquis) and the Arabic marzuban. The fiscal system was based on a land tax (kharag), a poll tax, and a number of transit and customs dues; the Sasanian assessment of taxable land, the divan-i marifat, survived in modified form under the early caliphate.

The Zoroastrian church was a parallel structure. The Zoroastrian high priest, the moabadan moabad, sat in council with the shahanshah and was, at moments of crisis, the effective head of the religious opposition. The Zoroastrian legal tradition, preserved in the Pahlavi Dastur-namag and Maten desturib, covered marriage, inheritance, contract, criminal law, and ritual purity. The Sasanian state patronised the church through land grants and tax exemptions; the church, in return, legitimated the dynasty through fire rituals, royal investiture, and the doctrine of the farr. The arrangement was not a theocracy, but it was not a strict separation of throne and altar either.

Coinage and the fiscal system

The Sasanian monetary system is one of the best documented in pre-Islamic Iran. The principal coin was the silver drachm, struck on the Attic standard at c. 4 grams and c. 90% silver, a degree of purity that the empire maintained, with occasional exceptions, for more than four centuries. The drachm circulated from the Mediterranean to the Pamirs and is the commonest Sasanian artefact in museum collections. The obverse shows the king in a distinctive crown, which changed with each reign, allowing art historians to identify individual kings and to date the coin series. The reverse shows a fire altar flanked by two attendants, a Zoroastrian motif that became the visual signature of the dynasty. The gold dinar was struck more rarely; the copper fals circulated locally.

The Sasanian fiscal system, however, came under increasing strain in the late sixth and early seventh century. The cost of paying the heavy cavalry, of maintaining the long frontier with Byzantium, and of the great building projects of Khosrow I and Khosrow II outran the state’s revenue. The coinage shows progressive debasement in the seventh century, and the Sasanian collapse of 628–651 CE has been read, by Michael Grant, Pourshariati, and others, as a fiscal-military crisis as much as a military defeat. The philological evidence is suggestive: the Pahlavi administrative vocabulary expanded in the late Sasanian period in ways that suggest bureaucratic improvisation under fiscal stress.

Shapur I and the wars of the third century

Shapur I (r. 240/42–270/72 CE) is the best-documented Sasanian ruler after Ardashir, and the most consequential. His trilingual inscription at the Ka’ba-ye Zartosht, the ŠKZ, gives his own account of three Roman campaigns: the first against Gordian III (defeated and killed at Misiche in 244 CE), the second against Philip the Arab (who bought a peace in 244), and the third against Valerian, whom Shapur captured at the Battle of Edessa in 260 CE — a Roman emperor taken alive by a foreign enemy, the first such disaster in Roman history. The Roman sources (Lactantius, De Mortibus Persecutorum 5) confirm the capture; the circumstances are debated.

The triumph of Shapur is commemorated in the great rock relief at Naqsh-e Rajab, where the Sasanian king sits on horseback with the Roman emperor kneeling before him, and in a related relief at the Ka’ba-ye Zartosht at Naqsh-e Rostam. The two reliefs are not identical — the triumph at Naqsh-e Rajab and the investiture at the Ka’ba-ye Zartosht are separate compositions — but they were conceived as a pair. The visual programme was imitated by later Sasanian kings and, in modified form, by the Umayyad and Abbasid caliphs.

Shapur’s internal policy was equally ambitious. He is credited with the foundation of the city of Bishapur in Fars, a Sasanian imperial capital built on Roman models and decorated with Roman mosaicists captured in the Syrian campaigns. He patronised the prophet Mani, founder of Manichaeism, and his son Hormizd I (r. 272–273) and grandson Bahram I (r. 273–276) continued this patronage. Bahram I’s successors turned on the Manichaeans; under Bahram II and then Shapur II, the prophet was imprisoned and killed (274/277), and the religion went underground. The Sasanian treatment of Christians, Jews, and Buddhists was more complicated, and I will come back to it.

The fourth and fifth centuries

The long reign of Shapur II (r. 309–379) was the great age of Sasanian military power in the fourth century. Shapur came to the throne as an infant and ruled for seventy years, fighting a long war with the Roman emperor Constantine and his successors that ended in a negotiated peace, consolidating the Sasanian hold on Armenia (with a major partition of the kingdom in 387 CE), and presiding over a long period of prosperity. Shapur II is the Sasanian king most associated with the persecution of Christians in the Sasanian east, but the persecution was intermittent and politically motivated; the Sasanian state was a constant home to large Christian communities, and the Church of the East survived and flourished under Sasanian rule.

The fifth century was a difficult period. Yazdegerd I (r. 399–420), called “the Sinner” by the Zoroastrian priesthood, pursued a policy of religious coexistence that got him into trouble with the church. Bahram V (r. 420–438), the Bahram Gur of the Shahnameh, was a Sasanian king of great popularity — his hunting exploits and his romance with the slave-girl Azadeh are among the most famous stories of the Persian epic — but he was unable to prevent the Hephthalite (White Hun) invasion of the eastern provinces. Yazdegerd II (r. 438–457) fought the Hephthalites to a standstill and persecuted the Christians of Azerbaijan, but he died on campaign. His son Peroz I (r. 459–484) was less fortunate; he was killed in battle against the Hephthalites in 484, and the Sasanian state was forced to pay tribute to the Hephthalite khagan for the next two decades.

The middle of the fifth century is the low point of Sasanian fortunes. The reign of Balash (r. 484–488), a brother of Peroz, was a brief interlude of recovery; he was deposed for his mildness. The reign of Kavad I (r. 488–496, 498–531) was more consequential. Kavad was twice deposed — once by the nobility, once by the Hephthalites — and twice restored. He is the Sasanian king most associated with the social movement of the Mazdakites, a religious-revolutionary sect whose economic programme of common property and redistribution alarmed the nobility. Kavad used the Mazdakite movement to break the power of the great families, then crushed it when it became inconvenient. His reign ended with a succession crisis; his son Khosrow I came to the throne in 531 and ruled for nearly fifty years.

Khosrow I Anushirvan

Khosrow I Anushirvan (r. 531–579) is the most famous Sasanian king, and with reason. He presided over what is, by most measures, the political and cultural zenith of the Sasanian state. His reign saw a long and inconclusive war with the Byzantine emperor Justinian in the 540s and 550s, ended by the “Eternal Peace” of 562 CE, by which the Byzantines agreed to pay an annual tribute of 30,000 solidi and the Sasanians abandoned their claims to the Black Sea coast. The war was ruinous on both sides; Procopius, the Byzantine historian who served in it, gives a vivid account of the Sasanian siege of Edessa and the Byzantine sack of Ctesiphon.

Khosrow’s internal policy was more lasting. He is credited with major fiscal and administrative reforms: a new land survey, a reassessment of the kharag, a reform of the tax bureaucracy, and a codification of the Sasanian legal tradition. The Pahlavi Maten desturib and the Dastur-namag of the later period are associated with his reign. He is also associated with the revival of the Academy of Gondeshapur, the multi-religious centre of learning in Khuzistan that had been founded under Shapur I and that, under Khosrow, became a major centre of Greek, Syriac, Indian, and Persian scholarship. The Greek philosophers who were closed out of the Athenian Academy by Justinian in 529 are said to have been received at the Sasanian court; the story is repeated in the Arabic tradition and may be partly true.

The cultural achievements of the reign are substantial but harder to pin down. The chess tradition (the Indian chaturanga became the Persian shatranj, transmitted westward to become the chess of medieval Europe) is associated with Khosrow’s court in the Arabic and Persian sources, though the legendary identification of the queen Shirin as the introducer belongs to a later stratum. The Khwatay-namag is traditionally associated with Khosrow’s patronage, though the text as we have it is a much later redaction. The Sasanian rock reliefs at Taq-e Bostan, with the great investiture and hunting scenes attributed to Khosrow II, are the most elaborate of the Sasanian period.

The late Sasanian crisis

The reign of Khosrow I was followed by a succession of weak kings. Hormizd IV (r. 579–590) was a competent ruler who was deposed and killed by the Sasanian general Bahram Chobin, who then usurped the throne for a year (590–591). Bahram Chobin is one of the great figures of the Sasanian epic; his war with the Byzantine emperor Maurice and the restoration of Khosrow II is the subject of one of the longest sections of the Shahnameh. The decisive engagement, in 591 CE, was fought at a site on the Mesopotamian plain; Howard-Johnston, in The Last Great War of Antiquity (2021), calls it simply the “591 CE battle” and refrains from the older and doubtful names. The result was a Byzantine-Sasanian restoration: Maurice helped put Khosrow II on the throne, and the Byzantines received territorial concessions and a defensive alliance in return.

Khosrow II (r. 590–628) is the last great Sasanian king, and the dynasty’s most extravagant. His early reign was brilliant; the Sasanian state, with Byzantine support, was restored to something like its Achaemenid extent. The murder of Maurice by the Byzantine usurper Phocas in 602 gave Khosrow a pretext for a war of revenge that turned into a general invasion. Between 611 and 621 CE, the Sasanian armies conquered Roman Syria, Palestine, Egypt, and parts of Anatolia; Jerusalem was taken in 614, the True Cross carried off to Ctesiphon, and the Byzantine state reduced to Anatolia and a fragment of North Africa.

The war turned in 622 CE, when the Byzantine emperor Heraclius took the field in person. Heraclius’ campaigns of 622–628, in which the Byzantine army struck deep into the Sasanian heartland, are the equal of any military operation in late antiquity. The Sasanian field armies were defeated in Azerbaijan; the peace of 628 restored the status quo of 602 and returned the True Cross. Khosrow II was overthrown and killed in 628 by a coalition of the Sasanian nobility, and a series of civil wars followed in which, by the Arabic sources, as many as twelve different claimants competed for the throne. The empire was further weakened by the plague of 627–628 CE, which swept through the Near East with devastating effect, and by a series of revolts in the southern Arab client kingdoms. By the time Yazdegerd III came to the throne as a child in 632, the Sasanian state was in no position to meet the Arab challenge.

Religion and learning

The Sasanian state was, in principle, a Zoroastrian state, and the Zoroastrian church was its principal religious institution. The Sasanian period saw the compilation of the Avestan canon in twenty-one nasks, of which only a fraction survives; the Vendidad and the Yasna are the most substantial Avestan texts, and the Pahlavi Zand is the basis of the surviving Zoroastrian tradition. The Bundahishn (the Primeval Creation), the Denkard (the Acts of the Religion), the Arda Viraf Namak (the Book of Arda Viraf), and the Zand-i Wahman Yasn (the Bahman Yasht) are the principal Pahlavi texts. Boyce’s Textual Sources for the Study of Zoroastrianism (1984) is the standard English introduction; Gnoli’s Zoroaster’s Time and Homeland (1980) and The Idea of Iran (1989) are the principal modern scholarly works on the Avestan period.

The Sasanian treatment of religious minorities is more complicated than the older nationalist narrative allowed. The Sasanian state persecuted the Manichaeans in the third century; the prophet Mani himself was killed under Bahram I in 274/277 CE, and the religion was driven underground. The Sasanian state had a complex and changing relationship with its Christian population, which was concentrated in Mesopotamia and numbered perhaps a quarter of the population of the Sasanian empire. There were major persecutions under Shapur II (c. 339 CE), Bahram V (c. 420), and Yazdegerd II (c. 455), but there were also long periods of coexistence. The Church of the East survived and flourished in Sasanian Mesopotamia; the Sasanian state had a strategic interest in the church as a counterweight to the Byzantine church, which was politically loyal to Constantinople. The Jewish communities of Mesopotamia, centred on the academies of Sura and Pumbedita, also flourished under Sasanian rule; the Babylonian Talmud was compiled in the Sasanian period.

The Sasanian intellectual centre was the Academy of Gondeshapur. The traditional date of its foundation is the third century under Shapur I, but the institution is best documented in the reign of Khosrow I. The Academy was a multi-religious, multi-lingual institution that brought together Greek, Syriac, Indian, and Persian scholars; it is the principal channel by which Greek medicine, philosophy, and science were transmitted to the early Islamic world. The institutional model of the Abbasid Bayt al-Hikma in ninth-century Baghdad, which is sometimes presented as a Sasanian restoration, is a more complicated story. Dimitri Gutas’ Greek Thought, Arabic Culture (1998) is the standard modern treatment of the transmission.

The Arab conquest

The Arab Muslim conquest of the 630s and 640s destroyed the Sasanian state in a series of military campaigns that, by the Arab sources, were over in less than two decades. The Battle of al-Qadisiyyah in 636 CE, in which the Sasanian spahbod Rustam Farrokhzad was killed and the Sasanian field army destroyed, is the conventional turning point. The sack of Ctesiphon in 637 CE followed; the Arab armies took the Sasanian capital, the imperial treasury, and the Sasanian queen Azarmidokht. The last Sasanian king, Yazdegerd III, fled eastward, first to Rayy, then to Khorasan, and was killed near Merv in 651 CE by a local official.

The Arab conquest was a military catastrophe of the first order. The Sasanian state had been weakened by the long war with Byzantium, by the fiscal crisis of the early seventh century, and by the civil wars of 628–632. The Arab conquest was also a cultural catastrophe. The Sasanian ruling class was destroyed or converted; the Zoroastrian church was reduced to a minority; the Pahlavi literary tradition went into a long eclipse from which it emerged only in the ninth and tenth centuries, in the form of the Zand literature and the revival Pahlavi texts of the early Islamic period. The Sasanian state did not die in 651; the Sasanian general Hormozan continued resistance in Khuzistan for several years after the fall of Ctesiphon, and the Pavis (or Pavii) revolts in Khorasan in the 650s and 660s were a serious problem for the caliphate.

Material culture

Sasanian art is the most visible legacy of the dynasty. The Sasanian rock reliefs at Naqsh-e Rostam, Naqsh-e Rajab, Bishapur, Firuzabad, Taq-e Bostan, and many other sites, and the Sasanian silver plate, of which several hundred pieces survive in the great museums of the world, are the principal bodies of evidence. The art is monumental, hierarchic, and obsessed with the visual rhetoric of kingship: the investiture scene, the triumph, the hunt. The iconography was imitated across Eurasia; the Sasanian hunting and roundel designs appear in the Byzantine, Central Asian, and Tang Chinese silks that travelled the Silk Road.

The Sasanian tradition of building is best preserved in the remains of Ctesiphon, Bishapur, Firuzabad, and Sarvestan. The defining element is the iwan, a vaulted hall open on one side, which became the hallmark of Persian monumental architecture for the next millennium. The great iwan of Khosrow at Ctesiphon, the Taq-i Kisra, with its parabolic vault of unreinforced brick c. 30 m high, was the largest unreinforced brick vault in the world at its construction and remained so for centuries. The Sasanian palace of Firuzabad, founded by Ardashir I, is a circular city of a kind unique in the ancient world. The Sasanian frontier system — the Gorgan wall in the northeast, the Sasanian fortifications of the Caucasus in the northwest, the system of marzbans and garrison cities along the Roman frontier — was the longest and most heavily garrisoned defensive network of late antiquity, and the Gorgan wall alone, at roughly 195 km, is the longest single pre-Islamic fortification wall outside China.

A final philological note

What the Sasanian evidence teaches, more than anything, is how to read a fragmentary tradition. The Pahlavi texts are mostly religious, mostly late, and mostly corrupted by centuries of scribal transmission. The rock reliefs are propagandistic. The Greek and Latin sources are from the other side. The Arabic sources are post-conquest. To make any of these speak for the Sasanian state is an act of triangulation, not of citation. The Pahlavi philologist sits at the centre of the evidence and reads everything else around it. The work is slow, and the conclusions are often tentative, but the cumulative effect, over a century and a half of modern scholarship, has been to recover a state that the older literature, drawing on the Greek and Latin sources alone, badly underestimated.