The Parthian Empire: Iran’s Second Imperial Dynasty
Hold a Parthian drachm up to the light. The silver is unusually pure, around 90 percent, struck on the Attic standard at roughly 4 grams. The obverse shows the king in profile, wearing the soft Parthian tiara with its pendant lappets and the torque of office around the neck. The reverse, in the later issues, shows an archer seated on a throne, the so-called archer type introduced in the late second century BCE. The drachms are common archaeological finds from the Caucasus to the Pamirs; they are the principal body of evidence for Parthian chronology, and they are the closest thing we have to a Parthian voice. The Parthians left few documents in their own language, and the Greek, Latin, Aramaic, and Chinese observers who recorded their doings were writing for other audiences. The coins are what survive.
The label “transitional regime” between Achaemenid and Sasanian is unfair. The Parthians ruled for nearly five hundred years, longer than the Achaemenids and about as long as the Sasanians. They were the eastern peer of Rome for two and a half centuries. They preserved the Achaemenid system of satrapal administration, in modified form, and they presided over the first long period of relative peace on the Silk Road. The Parthian achievement is harder to see than the Achaemenid or the Sasanian precisely because the Parthian-language sources are few. Bivar’s chapter in The Cambridge History of Iran vol. III (1983) is still the most thorough treatment in English. Curtis’s The Age of the Parthians (2007) is the useful counterweight. Wickersham’s work and the Parthian Sources Project (parthiansources.com) have begun to make the field navigable.
Origins
The Parthian state emerged from the vacuum that followed Alexander’s conquest in 330 BCE. The Seleucids, Macedonian kings ruling the eastern portion of the empire, governed through satraps whose attention was increasingly drawn westward by the long rivalry with Ptolemaic Egypt. Into this vacuum stepped the Parni, an Iranian-speaking people from the steppes east of the Caspian. Whether they were clients of the Seleucids dispatched to police the northern frontier, or independent opportunists, is a question the sources do not answer. Under their chieftain Arsaces, the Parni seized the satrapy of Parthia in or around 247 BCE — a date treated by later tradition as the founding of the empire — and over the next several decades absorbed Hyrcania and Aria and began to push into Media.
The early state was fragile. It was repeatedly attacked by the Seleucids. The real founder was Mithridates I (c. 171–138 BCE), among the most consequential rulers in pre-Islamic Iranian history. In a single generation he conquered Media, Mesopotamia, Elymais, and Persis, and in 141 BCE he entered Seleucia-on-the-Tigris, the great Greek-founded city that would serve as the Parthian winter capital. Ctesiphon, the sister-city across the Tigris, became the metropolis of the Arsacid dynasty and would remain a major centre of population and power for almost a millennium. The Seleucids were reduced to a rump kingdom in Syria.
Mithridates II (c. 124–88 BCE) consolidated the empire. He was the first Parthian ruler to use the title shāhān shāh, the Old Persian xšāyaθiya xšāyaθiyānām that the Achaemenids had used and that the Sasanians would inherit. He extended Parthian control into Armenia, where the dynasty installed a branch of the Arsacid house that would rule until 428 CE, and he signed the first formal treaty with the Roman Republic in 92 BCE, fixing the Euphrates as the boundary between the two powers. His silver drachms, modelled on the coinage of Alexander, became the standard currency of the Near East for the next three centuries.
A small caution. The claim that Mithridates II “reopened the trade routes with China” is plausible but should be qualified. The Han envoy Zhang Qian was active in Central Asia between 138 and 126 BCE, and contact between the Han and the Iranian world is attested from the early second century BCE onward, but the regular overland Silk Road traffic that would make Parthia the commercial pivot of Eurasia expanded only under his successors, in the first century BCE. The “Silk Road” as a continuous commercial artery is a 19th-century coinage of the German geographer Ferdinand von Richthofen, not an ancient term.
A federation in form
The Parthian state was, in form, a federation of kingdoms. At its head stood the shāhān shāh, ruling from a peripatetic court that moved between the winter capital of Ctesiphon on the Tigris and the summer capitals of Ecbatana in Media, Susa in Elam, and various royal residences in the Iranian heartland. Below the king stood a small number of great Parthian noble families — the Suren and the Karen are the best attested — whose members held the highest military and civil offices and whose marriage into the royal house gave them a powerful role in succession. The Arsacid monarchy was, in practice, elective within the broader royal house, and a council of nobles and princes had to confirm the accession of each new king. This system of shared rule produced both political stability and the chronic civil wars of the late Parthian period.
The empire was divided into roughly twenty provinces, a number broadly consistent with Pliny the Elder’s Natural History 6.41 and with the surviving Greek-language documents from Mesopotamia. Each province was governed in the king’s name, collected tribute, raised troops, and administered justice, but in practice the great Parthian nobles enjoyed a substantial degree of autonomy, and in some regions, particularly in Mesopotamia and in Elymais, local dynasts ruled almost as independent kings. The Parthian system of rule has often been called feudal, and the comparison has some force, though it obscures the centralised character of the state in its early and middle periods and the role of a Greek-style bureaucracy in the western provinces.
The Parthian chancery used Greek as its principal written language. The surviving documents from Nisa, Dura-Europos, and other sites show a sophisticated system of administrative writing, including letters, contracts, tax receipts, and royal decrees. The Nisa ostraca, the largest body of Parthian-language documents, record transactions in wine from the royal estate at Mithridatkert, the old Parthian capital in modern Turkmenistan. The Hellenistic paradeisoi, the royal hunting parks that were a feature of the Seleucid and Parthian Near East, are better attested than the granaries of the older popular literature; the agricultural wealth of the empire came mainly from the broad farms of Mesopotamia and from the irrigation systems of the Tigris-Euphrates valley.
Society
Parthian society was sharply stratified. At the top stood the Arsacid royal house and the great noble clans, who held enormous land grants, commanded the heavy cavalry, and provided the king with his inner circle. Below them was a class of lesser nobility, drawn from the older Iranian aristocratic families and from the Greek and Hellenised urban populations of Mesopotamia. Beneath the nobility stood the free Iranian peasantry, who formed the backbone of the light cavalry and the infantry, and the urban artisans and merchants of the Mesopotamian and Iranian cities. At the bottom of the social pyramid were slaves, many of them prisoners of war or debt-bonded peasants.
The economy of the Parthian Empire was prosperous. The agricultural lands of Mesopotamia were among the most productive of the ancient world, and the Parthian control of the overland Silk Road generated large transit revenues. The Parthian state was a major exporter of textiles, carpets, precious metals, and gems. Pliny the Elder (Natural History 12.41) put the Roman outflow at 50 million sesterces a year in the early first century CE, but modern historians generally regard this figure as an exaggeration. The balance-of-payments problem was a recurrent concern of Roman imperial policy.
The great cities of the Parthian empire were a striking feature of its economic life. Ctesiphon, on the Tigris near modern Baghdad, was the principal capital and grew to a population of perhaps half a million at its height — comparable, in the first century CE, to the largest cities of the Roman Mediterranean. Seleucia-on-the-Tigris, founded as a Hellenistic colony by Seleucus I Nicator around 305 BCE, remained a major commercial and intellectual centre. Ecbatana, the old Median capital, served as a summer capital. Susa, the ancient Elamite capital, continued as a regional centre. Other urban centres included Hecatompylos, the original Parthian capital; Merv in Central Asia, a major Silk Road hub; and Rhagae (modern Rey, near Tehran), a major Iranian city.
Culture and religion
The cultural life of the Parthian Empire was a synthesis of Greek, Mesopotamian, and Iranian elements. In the western provinces, Greek remained a language of administration and high culture well into the second century CE, and the cities of the Tigris and Euphrates preserved their Greek-style theatres, gymnasia, and civic institutions. The Parthian court was bilingual: the kings used Greek for their official inscriptions and seals, while the nobility and the Zoroastrian priesthood used Middle Persian and Parthian, the two western Middle Iranian languages that emerged as literary vehicles during the Arsacid period. The Avesta, the sacred scripture of Zoroastrianism, was probably codified in something like its present form during the Parthian period, though the surviving Avestan texts show signs of having been committed to writing only in the Sasanian era from a long oral tradition.
Parthian metalwork, in particular the great silver plates, rhytons, and drinking vessels of the first and second centuries CE, shows a hybrid style in which Greek, Iranian, and steppe elements combine. Some of the plates, now in the British Museum, the Metropolitan, and the Hermitage, show royal investiture scenes in which the king receives a ring from a deity — a motif that was also used by the later Sasanians, though the direction of influence is debated. The Sasanian claim to have invented the investiture-ring motif is not sustainable; Parthian prototypes are attested.
Parthian architecture is less well preserved than that of the Achaemenids and the Sasanians. The Parthian capital at Ctesiphon included a great hall whose remains were later incorporated into the Sasanian palace of Khosrow I (the taq-i kisra, with its c. 30 m parabolic vault, is a Sasanian building, not Parthian). The Parthian city of Hatra, in the Jazira of modern Iraq, was an unusually well-preserved example of Parthian urban architecture, with a grid plan, fortified walls, and a series of great temple complexes that combined Greek, Mesopotamian, and Iranian styles. The Parthian cities of Dura-Europos, Seleucia, and Ctesiphon have been the subject of major archaeological investigations that have transformed our understanding of Parthian material culture.
The official religion of the Parthian state was Zoroastrianism. The Parthian kings, however, were notably tolerant of other religions. The Jewish communities of Mesopotamia, augmented by refugees from the Roman destruction of Jerusalem in 70 CE, flourished under Parthian rule. Christian communities also began to take root in Mesopotamia in the first and second centuries CE, and the Parthian period saw the establishment of the Church of the East, which would become one of the great Christian communions of the pre-Islamic world. The claim that the Parthian ruling class converted to Buddhism is a non sequitur unsupported by the evidence. The Parthian elite remained Zoroastrian, with a veneer of Hellenistic syncretism in the western provinces.
The Parthian army
The Parthian army, like the Achaemenid, was a multi-ethnic force built around a core of Iranian heavy and light cavalry, supplemented by mercenary infantry from the Hellenistic east, by client troops from the Arab and Armenian kingdoms, and by feudal levies from the great noble houses. The Parthian army is best remembered for two units: the horse archers, mounted bowmen who wore little or no armour and fought with a powerful composite bow, and the cataphracts, heavily armoured lancers whose men and horses were sheathed in scale or mail. Together these two arms formed a tactical system whose effectiveness against heavy infantry was demonstrated time and again against the Romans.
The Parthian doctrine of cavalry combat has been studied by military historians from Vegetius to the present day. The essence was to feign retreat, draw the enemy out of formation, and then turn and destroy him with concentrated missile and shock action. The doctrine was not original to the Parthians — steppe peoples had used similar tactics for centuries — but the Parthians refined it into a system, supported it with excellent training, and integrated it with reserves of cataphracts held in the second line. The “Parthian shot,” a Greco-Roman term for the act of an archer turning in the saddle to fire on a pursuer, became a Roman literary topos and is the most recognisable military contribution of the Arsacid state.
The wars with Rome
The Parthian Empire and Rome were the two great powers of the ancient Mediterranean world, and their interaction, from the mid-first century BCE to the third century CE, shaped the political history of the Near East. The first major conflict was the Battle of Carrhae in 53 BCE, in which the Parthian general Surena destroyed the legions of Marcus Licinius Crassus and captured the Roman eagle standards, an event that sent shock waves through the Roman world. The standards were returned to Rome in 20 BCE under Augustus, in a negotiated settlement that marked the de facto recognition of the Parthian frontier on the Euphrates.
The wars of the first and second centuries CE were largely inconclusive. Trajan, emperor from 98 to 117 CE, invaded Parthia in 115 and captured Ctesiphon, Seleucia, and the Tigris-Euphrates valley as far as the Persian Gulf. His successor Hadrian withdrew from the newly conquered territories and made peace with the Parthian king Osroes I, establishing a Roman policy of containment on the Euphrates that would last almost a century. The emperor Lucius Verus, co-ruler with Marcus Aurelius from 161 to 166 CE, fought a more successful war in the 160s, capturing Ctesiphon and forcing the Parthian king Vologases IV to cede northern Mesopotamia. The emperor Septimius Severus invaded Parthia in 195 and again in 197–198, capturing Ctesiphon and Babylon and adding the Roman province of Mesopotamia to the empire.
The Parthian response to Roman pressure was as much diplomatic as military. The Arsacid court maintained close relations with the Jewish and Arab populations of the Roman Near East, supported Roman rebels and usurpers, and intervened in the Jewish revolts of 66–73 and 132–135 CE in ways that sometimes brought the empire to the brink of war with Rome. The Arsacid kings also intervened in the affairs of Armenia, the buffer kingdom between the two empires, and the contest for Armenian succession was a recurrent source of friction.
Decline
The Parthian state entered a long decline in the late second century CE. The empire was repeatedly shaken by internal civil war, by the loss of Roman markets to internal disruption, and by the rise of a new Iranian dynasty in Persis, the Sasanians, who claimed descent from the Achaemenids. The decisive moment came in 224 CE at the Battle of Hormizdagan, where Ardashir I defeated and killed Artabanus IV. The Arsacid royal house was exterminated; the great noble houses were stripped of their political power; a new, more centralised, more aggressively Zoroastrian state took its place.
The fall of the Parthian Empire was not a sudden event but a long process. The state had been weakened by decades of costly war with Rome, by the secession of subordinate kingdoms in the Caucasus and the Iranian heartland, and by the economic disruption caused by the Antonine and Cyprian plagues of the second century CE. The Parthian state survived for centuries, but its political coherence was undermined by the increasing power of the great noble houses, by the alienation of the Greek-speaking populations of Mesopotamia, and by the failure of the royal house to develop a stable system of succession. Pourshariati’s Decline and Fall of the Sasanian Empire (2008) has shown, against the older view, that the Sasanian revolution was not a simple overthrow of an alien dynasty by a national one but a more complex political realignment in which Arsacid noble houses were absorbed into the new order.
The end of the Arsacid dynasty in 224 CE was not the end of the Arsacid line. Members of the Arsacid house survived as kings of Armenia, Iberia (Georgia), and Caucasian Albania well into the fifth century, and the Armenian Arsacid dynasty ruled until 428 CE. The Sasanian kings of the third and fourth centuries often married Arsacid princesses, and Arsacid blood was considered an essential qualification for legitimate kingship among the Iranian aristocracy.
The Arsacid line in outline
The real founders of the empire were Mithridates I and his successors. Mithridates I (c. 171–138 BCE) was the first great Parthian king. He consolidated the conquests of his predecessors, expanded the empire into Media and Mesopotamia, and made Ctesiphon the imperial capital. He was succeeded by Phraates II (c. 138–127 BCE), who faced a major invasion by the Seleucid king Antiochus VII and defeated the Seleucids at the cost of substantial Parthian losses. Artabanus I (c. 127–124 BCE) was a short-reigning king who faced a major invasion of the Saka, the nomadic peoples of the Central Asian steppes. Mithridates II the Great (c. 124–88 BCE) was the longest-reigning of the early Arsacid kings and the first to use the title shāhān shāh. He signed the first formal treaty with Rome in 92 BCE, and the silver drachm he established became the standard currency of the Near East.
The later Arsacid kings include Orodes I (c. 90–80 BCE), under whom the great general Surena destroyed Crassus at Carrhae; Phraates IV, who returned the Roman standards to Augustus in 20 BCE; Vologases I (c. 51–78 CE), who built Vologesias and faced the great Jewish revolt of 66–73 CE; the series of Vologases III, IV, and V, who ruled during the wars with Lucius Verus in the 160s CE; and the long line of kings of the late second and early third centuries who presided over the slow decline of the dynasty. The last Arsacid king, Artabanus IV (c. 213–224 CE), ruled an empire in deep crisis, defeated Caracalla’s invasion and then Macrinus’s counter-invasion at Nisibis in 217 CE, and was killed by Ardashir I at the Battle of Hormizdagan in 224 CE.
Legacy
The Parthian legacy is substantial. Politically, the Parthian state preserved the Iranian imperial idea for nearly five centuries, and the Sasanian revolution of 224 CE was in significant measure a Parthian restoration. Culturally, the Parthian period saw the codification of Zoroastrianism in something close to the form in which it would be known to the Islamic world, and the emergence of a distinctive Iranian Hellenistic art style that blended Greek, Mesopotamian, and Iranian elements. Linguistically, the Parthian period saw the emergence of Middle Persian and Parthian as literary languages and the development of the Pahlavi script. Militarily, the Parthian doctrine of horse archery and cataphracts shaped the cavalry warfare of late antiquity and was imitated by the Sasanians, the Byzantines, the Avars, the Magyars, the Mongols, and the early Islamic armies. The Parthian shot, in particular, has become a permanent part of the vocabulary of mounted warfare.
The Parthian Empire is the bridge between the Achaemenid and Sasanian empires, and its memory is an important part of modern Iranian national identity. The Arsacid line, in particular, is celebrated in modern Iranian historiography as one of the great national dynasties, and the Farsi term Parthian and the Sasanian term Pahlavi are both used in modern Iran to refer to the pre-Islamic past.
The Parthian period is also of central importance in the history of the Middle East, of Central Asia, and of the Roman world, and the study of the Parthian Empire is essential to an understanding of the ancient world as a whole. The chief scholarly anchors remain Bivar (1983), Curtis (2007), Wiesehöfer (2001), and Pourshariati (2008), with the Parthian Sources Project the best starting point for primary texts.
A final observation, because the Parthian period is where the methodological lessons of the field bite hardest. The Parthian evidence is, by ancient standards, thin, and the temptation to over-read it is constant. The four-thousand Parthian drachms in the British Museum, the few hundred inscribed ostraca from Nisa, the Sasanian-era copies of older Arsacid material, the Greek and Roman sources written for non-Iranian audiences — none of this is enough to ground a confident political history of a dynasty that lasted half a millennium. The recent work of Ali Mousavi, Gholamreza Karamian, and Mostafa Fakheri on the Parthian frontier forts, and the ongoing Italian-Iranian excavations at Old Nisa, are adding to the picture, but the rate of new evidence is slow. To write about the Parthians is, more than for the Achaemenids or the Sasanians, to write from inference and silence, and the inference has to be flagged as inference.