The Persian, Parthian and Sasanid empires were major states in the ancient world. Their governmental structures had strengths as well as weaknesses, which profoundly influenced their histories. 

The term “Persian civilization" can refer to two distinct, but closely related cultural entities, Pre-Islamic Persian civilization and Islamic Persian civilization. Pre-Islamic civilization in turn falls into two main periods: first, that of the great Persian empire of the Achaemenid kings (c. 550 BC to c. 330 BC); and second, that of the Parthian and Sasanian empires (c. 140 BC to c. 640 AD). These two periods are punctuated by the Greek-Macedonian occupation of Iran under Alexander the Great and his successors.


This article deals with the government and politics of the great pre-Islamic Iranian empires.





The Iranian peoples were a branch of the Indo-European group of peoples who had spread out across the steppes of central Asia from the 4th millennium BC, propelled by their nomadic lifestyle. A group of eastern Indo-European peoples, who called themselves the “Aryans” (or “Iranians”) moved down into Iran and the western Indian subcontinent (modern-day Pakistan). In India they would go on to play a pivotal role in that subcontinent’s history. In Iran, they slowly spread out over a huge area, from the Hindu Kush mountains on the east to the Caucasus and Zagros mountains in the west, and down to the Indian Ocean in the south. Along with those who remained on the steppes of central Asia, the Iranians covered what is now Iran, Afghanistan, Tajikistan, Kyrgyzstan, Turkmenistan, Azerbaijan, and parts of Iraq and Turkey.


Although by the 7th century BC the Iranians were divided into many different tribes - Parthians, Sogdians, Bactrians, Medes and Persians, for example - they remained very conscious of their Iranian (or “Aryan”) identity.


During the 7th century many of the Iranians came under the control of one of these tribes, the Medes, who seem to have formed them into a fairly loose confederacy, with vassal kings subordinated to the Mede “King of Kings”. In the mid-6th century BC one of these vassal kings was called Cyrus, who ruled an Iranian tribe called the Persians. They lived in modern-day Fars province (i.e. Persia), a fairly mountainous and inaccessible corner of southwestern Iran.


Cyrus (“the Great”) rebelled against his overlord, the King of the Medes, and, defeating him in battle, replaced him as “King of Kings”. He and his immediate successors then went on to conquer a multinational empire of unprecedented size - the largest in the world at that time, and indeed the largest (by area) in the whole of ancient history. This empire is often known as the "Achaemenid empire" (after the dynasty which ruled it), and we shall use this term here to differentiate it from the Parthian and Sasanian empires which came later.


Cyrus’ successor-but-one, Darius I (also called “the Great”, reigned 522-486 BC), set the empire on a sound administrative footing. Such was his achievement that it was able to endure for nearly two hundred years after his time. Finally, in a ten-year period from 334 BC, the huge empire was in its turn conquered by the army of Alexander the Great


A multicultural empire


The Persian empire ruled a multicultural, multiethnic empire of some 50 million inhabitants. Of these, the Persians, and to a lesser extent the other Iranian tribes, occupied a privileged position. Beyond the lands of the Iranians, to the east the empire covered western parts of the Indian subcontinent; to the west, it took in Mesopotamia, Syria (including Judaea), Asia Minor (including the Greek city-states of Ionia), Armenia, Cyprus, Egypt and Cyrenaica. At times it also included parts of Europe up to the river Danube, including Thrace and Macedonia


After Alexander's early death in 323 BC, his empire was divided between his leading generals, and Iran, Mesopotamia and the other eastern provinces of Alexander's empire fell to Seleucus and his descendants. Like other former former Persian provinces, the Iranians now found themselves under alien rule, and excluded from power. Greek-style cities were founded throughout the land, each a centre of Greek civilization. Greek became the language of government, and Greek art, architecture and literature were favoured by the Macedonian and Greek ruling classes over native cultural expressions.


In Iran, this Hellenistic period (as it is called, after the “Hellenes”, the name by which the Greeks called themselves) was an interlude of foreign rule which lasted for some 150 years, and was brought to an end by the conquests of the Parthians. These were an Iranian people who drove the Seleucids out of Iran and Mesopotamia and formed their own empire. 

history map of the persian empire


View map of the Persian empire in the atlas

The Parthian empire was smaller than the Achaemenid empire had been: it did not include Asia Minor, Syria or Egypt, which remained under Hellenistic rulers, and then fell to the Roman empire. However, the Parthian state remained in existence for almost 400 years, before being replaced by the Sasanian empire in the years around 224 AD.


The Sasanians hailed from that region of Iran from which the rulers of the Achaemenid empire had come, almost seven hundred years before. They claimed to be of pure Persian descent, descendants indeed of the old Achaemenid royal family; and they championed a pure Persianism which was closely associated with the ancient Iranian religion of Zoroastrianism.

The Sasanian empire lasted for more than 400 years. At its height it was much larger than the Parthian empire had been, incorporating large parts of eastern Iran, central Asia and Afghanistan. The western regions of Asia Minor, Syria and Egypt remained outside its borders, however, except for a bried period in the early 7th century - just before the empire succumbed to the great Muslim conquests of the mid-7th century AD.


Politics at the centre: kings, nobles and clerics


So far as government and the state apparatus are concerned, we know much more about the Achaemenid empire than its successors. For most of ancient times Iranian culture was predominantly an oral one, producing no great body of written literature of its own; it therefore produced no native historians. During Achaemenid times, however, Greek authors, above all Herodotus, took a keen interest in the Persian empire, and have left us detailed descriptions of its history and how it worked. For the Parthian and Sasanian empires there is no such description, just scraps left by some Roman authors. 


The settled peoples of the Middle East who were conquered by the Achaemenids had long been accustomed to being governed by all-powerful sovereigns, and the Persian kings stepped into this role. To the people of Mesopotamia they claimed to be the successors of the kings of Babylon, ruling by the favour of Marduk, the chief god of the Babylonians. To the people of Egypt they claimed to be the heirs of the pharaohs - and within Egypt, therefore, divine. To the rest of their subjects they made no claim to divinity, but they did claim to rule by favour of the chief of the Iranian gods, Ahura Mazda, who had bestowed the empire on them. They ruled as his representative on earth, and in return he required them to be friends “to right, not to wrong”. To help them in their task Ahura Mazda bestowed “wisdom and strength” on them so that they were valiant warriors, wise leaders and just law givers. Their person was sacred, and they possessed an abundance of royal charisma. As one of their greatest monarchs said of himself, “I am Darius, the great king, king of kings, king of the countries….an Achaemenid.”


The traditional elites within Iranian society had difficulty adjusting to what was for them a new political situation. The Iranian peoples had originally been nomadic herdsmen on the steppes of central Asia. Amongst such peoples, kings were often "first among equals" rather than unquestioned rulers, and this seems to have been the case amongst the Iranians. After many of the Iranian tribes had settled down, their society remained dominated by a powerful nobility, who had now become a class of great landowners with quasi-feudal authority over the rest of the population. The nobility was keen to preserve its political influence viz-a-viz both king and people, and was supported in this by the traditional religious leaders of the Iranians, a group known as the magi. In the reign of the second Achaemenid king, Cyrus' son, Cambyses, nobles and clerics rebelled, and the next king, Darius, had to fight against these elements to gain the throne.


Darius was successful in asserting royal authority against nobles and clerics, but the tradition of aristocratic political influence was maintained to some extent in the privileges accorded to the high nobility. The leaders of the “seven great families” were especially privileged: they seem to have formed a council which was consulted on major matters of state, and along with members of the royal family, they seem almost to have monopolized the highest offices of state.


The fact that, when they came to power, the Parthians had only recently come from the steppes may have reinforced their nobles' power. Like their Achaemenid predecessors the Parthian kings filled the topmost positions of state with members of the nobility, but unlike them they were never able to bring that class fully under control. From time to time kings might exert their power over individuals: the execution of the great general who inflicted one of the greatest defeats on the Romans, at the battle of Carrhae (53 BC), is a grizzly example of the arbitrary royal violence that could be meted out. But more frequently it was the nobles who meted out the violence; they assassinated or ousted many of the Parthian kings from power.


Without strong kings to hold factionalism at court in check, political instability became endemic and increasingly undermined any effective government within the Parthian empire.


Under the Sasanian empire the nobility - made up of more or less the same powerful families as under the Parthians - continued to be a thorn in the side of the kings, though not to the same extent. Under strong kings the nobility’s power might wane, but it would come back again when inevitably a less effective ruler came to the throne. Just as under the Parthians, the nobles continued to oppose any attempts to downgrade their privileges, or even to go against policies they espoused. For example, the parochialism of the bulk of the nobles meant that they tended to be more belligerent than the kings, whose wider view of things made them see more clearly the downsides of war - the drain on the royal treasury and wider economy, the military vulnerability, the advantages of peace. Especially when it came to the Romans, the nobles were deeply suspicious of any attempts at a rapprochement, and more than one king was deposed or murdered because of this issue.


For much of the Sasanian period the nobility had a staunch ally in the Zoroastrian clergy. Zoroastrianism became the state religion of the Sasanian empire, and the higher clergy were determined to maintain their powerful position at court. They frequently attempted to thwart the wishes of the kings, and in this were aided by the nobility.


One of the main agendas of the Zoroastrian leaders was to draw all religious authority into their own hands. From time to time they influenced the state to engage in active persecution of other faiths - Christians, Jews, and heterodox sects of Iranian origin such as Manichaeism. When Christianity became the official religion of the Sasanian regime's great enemy, the Romans, after Constantine’s time, the persecution of the Christians intensified. They were viewed with great suspicion as a real or potential fifth column of Roman sympathisers. The Zoroastrian church bolstered its power by organizing itself along the same lines as the Christian church in the Roman empire, with a hierarchy of senior and junior clergy under discipline to promote orthodox beliefs. 


In later Sasanian times some of the fire seems to have gone out of the higher clergy, or perhaps they lost some of their hold at court. This was probably linked to the fact that relations between Christians and the Sasanian state were mellowing, as most of the Christians within the empire adopted a branch of Christianity (Nestorianism) which the Roman emperors were determined to stamp out. Later Sasanian kings, indeed, tended to present themselves as protectors of Christianity.


The imperial capitals


The Achaemenid kings spent most of his time, when not on campaign, in one of four cities in Iran. Parsagadae, built by Cyrus the Great, and Persepolis, founded by Darius the Great and completed by his successors, lay in the modern province of Fars, in the southwest of Iran. This was the Persian homeland, but being comparatively inaccessible their main role was as centres of royal ceremony. Susa, the capital of the ancient kingdom of Elam and well-located on major routes, functioned as the chief seat of government, with Ecbatana, the old capital of the Medes, a summer retreat. All these cities were lavishly embellished by successive Achaemenid kings with magnificent palaces.


One city outside Iran also functioned as a subsidiary capital of the Achaemenid empire. This was the great historic city of Babylon, in Mesopotamia. Some of the kings spent much of their reigns here.


The Seleucids built a new city for their eastern capital, Seleucia (their western capital was at Antioch, in Syria). Seleucia was located near to Babylon, in Mesopotamia, and although, like all Seleucid foundations, it was initially settled by Greeks and Macedonians, many of Babylon's inhabitants also moved to the new capital. Seleucia became one of the largest cities in the Hellenistic world, while Babylon now went into steep decline.


Under the Parthians Susa was again chosen as a capital, but for their main capital they too built a new city, called Ctesiphon. In fact it was just across the river Tigris from Seleucia, and formed a twin city with it. Ctesiphon remained the capital under the Sasanian empire, and was one of the largest cities in the world at that time, with, by some estimates, a population of 600,000 people. Susa continued to functioning as the subsidiary capital.




The central administration under the Achaemenids


Royal palaces lay at the heart of the administration of all the Iranian empires under discussion. It is the Achaemenid administration about which we know most, and some of the vast stream of correspondence flowing to and from the royal courst has survived. This correspondence was dealt with by a large and complex secretariat, organized along Babylonian lines and operating according to practices developed over thousands of years of Mesopotamian history. Presumably some of this secretariat accompanied the king wherever he might be, but its permanent headquarters seems to have been at Susa. The chief cities in each satrapy had a smaller version of this body.


The central bureaucracy also handled the flow of tribute which came in from the satrapies. This came in, not only in silver and gold coin, but in ivory, cattle, corn wine, oil, and all manner of other commodities. Huge warehouses were located in Susa, Ecbatana and Babylon to store this tribute, and a large staff of officials, also presumably operating along Babylonian administrative lines, disbursed this to pay the king’s servants and officials, the army, the expenses for public works such as the construction of palaces, roads, and canals, and the manifold other demands on the royal treasury.


Official correspondence, initially in Elamite, was later mostly in Aramaic, which had already become the language of state in Assyrian times. In those countries where Aramaic was not widely understood, national languages and scripts were used: demotic writing in Egypt, Greek in Ionia, in western Asia Minor, and Elamite in the territory of the old Elamite kingdom and, indeed, in Persia too, at least until about 460 BC when Aramaic replaced it.


Communication between centre and provinces was facilitated by an excellent (for the time) road network - vital in such as extensive state as the Persian empire. The roads allowed a regular government postal service to operate. Such a service had first been developed by the Assyrians, and was based on relay stations located at regular intervals along the roads. These enabled couriers to have fresh remounts day and night, so that they could cover the distance from Sardis in Asia Minor to Susa in Iran in only seven days.


Provincial administration under the Achaemenids


The Persian empire, as we have already stated, was a huge multinational state. For purposes of administration it was divided into about twenty large provinces, called satrapies (the number varied from time to time as some were merged, some divided, or borders between them changed). The only part of the empire not assigned to a satrapy was Fars (or Persis, as it was then called), which was regarded as being ruled directly by the king himself.


The governors of these satrapies were appointed by the king, whom they represented within their territories. Just as the king’s power was absolute throughout the empire, so theirs’ was absolute within their satrapies. They dispensed justice, collected tribute, negotiated with nearby states beyond the empire’s borders, and were commander’s in chief of the troops stationed within their borders. The governors' (satraps’) courts and administrations were smaller copies of the royal ones.


The men appointed to be satraps were mostly princes of the Persian royal family or senior members of the high Persian nobility. To check the power of these potentially over-mighty governors, the satraps were regularly visited by royal inspectors, called “the king’s eyes”, who traveled all over the empire and reported directly to the king.


As we have seen, one of the prime duties of a satrap and his staff was the collection of tribute from the populations under his control. This function was often farmed out to tax farmers. These often operated as companies, who provided the up-front sum and then made their profit by taking what they could from the population. This  was a very widespread practice in the ancient world, and indeed right up to modern times, as it obviated the need for the state to employ its own large bureaucracy for this purpose. However, wherever it was found the practice was open to abuse, and the Persian empire was no exception.


Just as the Persian homeland (modern-day Fars province in Iran) was not governed by a satrap, neither was it subject to tribute. The other Iranian peoples (Medes, Parthians and so on) were under satraps and did have to pay tribute, but at a lower rate than non-Iranian subjects of the empire. To ensure a fair assessments of tribute, Darius had sent a commission of trusted men to evaluate the revenues and expenditures of each satrapy. These rates, however, never seem to have been adjusted in later times, and this must have led to a growing disparity between a region’s tax liability and its ability to pay.


Each satrapy was divided into local districts, with their own governors. These could be appointed by the royal court, but they could also be nominated by the satrap. Sometimes local peoples were under their own native rulers, who retained their positions so long as they fulfilled their obligations to the Persian government. Thus the re-established community in Jerusalem had a succession of Jewish officials as their governors.


Achaemenid Imperialism


The Achaemenid kings allowed the conquered peoples within their empire a large measure of autonomy. In Babylonia, for example, they kept the administrative apparatus of the late Babylonian empire in place; similarly, they maintained the ancient institutions of Pharaonic Egypt; the Phoenician cities of Tyre and Sidon remained under native leaders, as did the Jews in Jerusalem. 


Likewise, there was no attempt at “cultural imperialism”. The different peoples where allowed to keep their own customs, religions, laws, languages and so on. Indeed the Achaemenid kings went out of their way to promote their subjects’ identities. The most famous instance of this is the official encouragement successive Achaemenid kings gave to the Jews in returning from exile and rebuilding the temple and city walls of Jerusalem. Another example is that Darius commissioned the codification of the laws of Egypt.


This policy paid dividends: the Babylonians acknowledged Cyrus as rightful successor of Nebuchadnezzar and Nabonidus, and the Egyptians recognized Cambyses as founder of a legitimate new dynasty of pharaohs; and the Jews looked to the Persian kings with gratitude and loyalty, regarding them as deliverers sent by God.


Administration under the Seleucids, Parthians and Sasanians

The Achaemenid pattern of imperial administration was followed by the Seleucids. Under them, there was an increasing tendency for satraps and local dynasts to become autonomous, particularly in the eastern parts of their empire. This trend continued under the Parthian kings, who delegated much of their power to local rulers as vassals of the Parthian "king of kings"Indeed, the in-fighting at court which we have referred to above created such a power vacuum that the local rulers were able to more or less go their own way, governing their territories as virtually sovereign princes. In the later Parthian empire they scarcely acknowledged the authority of the kings at all. The exception was in times of major foreign invasion, which of course threatened their own positions as much as the Parthian king's; but generally, the later Parthian empire was hardly more than a collection of independent states.

The Sasanians reversed this situation to a large extent. Their state was more centralized than the Parthians’ had been, with various kings vigorously seeking to concentrate more power in their own hands. In the process they built up a sophisticated imperial administration, staffed by a hierarchy of career bureaucrats who were able to co-ordinate the economic activities of the state with real efficiency. In the provinces they replaced the native local dynasties with princes of the Sasanian royal family. The process of centralization was never completed, however, and provincial governors always remained very powerful figures. 




The Achaemenids, as we have seen above, allowed the different peoples to keep their own laws. This is most clearly seen in the thousands of court texts which have survived from Babylonia, which show that the law as practiced there stood four-square in the tradition of Hammurabi, who reigned more than a thousand years before.


However, a multinational empire requires an overarching legal framework by which all its peoples could resolve differences and have justice done to them, even if they come from different cultures. This framework was naturally provided by Persian law, but heavily adapted by the Achaemenids to deal with a more cosmopolitan world. This basically involved importing major influences from the Babylonian legal tradition into it, particularly to do with civil and commercial law.


No Achaemenid law code has survived, and probably none ever existed. However, the kings paid great attention to legal matters. Darius’ inscriptions clearly underline the importance he attached his role as a lawgiver, and his reputation in the ancient world was such that even the great Greek philosopher Plato would praise him as the model of a good lawgiver and king, since by his laws the Persian empire had been preserved “up to now” (i.e. Plato’s own day, late 5th/early 4th centuries BC).


For the Persians, the king’s law was the gods' law, and as such applied to the whole empire. Every royal decree was considered irrefutable and unchangeable law, to be obeyed by all his subjects. This divinely-sanctioned law could thus be used to enforce obedience to the king; but it could also ensure that, for example, merchants from different nations could resort to a Persian court to resolve any business disputes between them.


The king appointed a panel of special judges (all Persians) to advise him on legal matters and to try cases in his name; the satraps had similar panels to aid them dispense justice within their provinces. 


These judges were experts in interpreting the ancient laws. In doing this they followed the traditional Persian principle of close examination of the facts of a case and paying attention to the previous character of the individuals involved. In criminal cases, the punishment meted out by Persian courts was, by modern standards, frighteningly cruel: execution by crucifixion or impalement was common; mutilation was a standard punishment, as was banishment. These punishments, however, were normal in the ancient Middle East, and the Achaemenid legal system had a reputation for humanity. The punishment was to fit the crime, and before reaching a harsh verdict, the judge had to take into account an offender’s past record: if his good deeds outweighed his bad he would not be punished for just one crime. 


Achaemenid kings took justice very seriously; Greek authors mention several cases of corrupt judges being sentenced to death. The great achievement of the Achaemenids was to provide a legal system which enabled all their subjects to have a large measure of confidence that, in the last resort, they would receive justice, even if those involved in a case came from different races and cultures.


Law in Parthian and Sasanian times


We know next to nothing about the administration and practice of law under the Parthians. However, we have a major written source on legal matters from Sasanian times, The Book of a Thousand Judgements, which gives us a great deal of information about how the law operated at that time (although skewered towards religious applications), and it is very likely that much of this was applicable to the Parthian period as well.


These texts show that there were various levels of courts in every rural area, district, city and province of the empire. Appeals could be made from a lower to a higher court, right up to the chief justice of the empire - who was the high priest of the Zoroastrian church. 


Much Sasanian law was concerned with religious matters, and in fact the courts seem to have largely been a branch of the Zoroastrian church.


Court procedures were set out very fully. Full records of trials were kept for further reference if need be. Judges acted as prosecutors as well as judge, and in fact two judges were often appointed, one for each of the parties involved. Both parties were also allowed to have their own lawyers, some of whom were professionals, others of whom were local dignitaries who were fulfilling this role out of charity. If a case was impossible to decide by the usual means, resort was made to the ordeal, such as passing through fire. Judges were allowed to get a confession by putting the accused to torture. 


The Sasanian jurists disagreed on the validity of the testimony of women. The doubts tended to stem from women’s dependence on males (husband or father), which might compromise their testimony; the same was true for children or slaves. Civil law allowed the testimony of an independent woman, or of a legitimate wife who has no interest in the dispute.


Sasanian law (and no doubt previous Iranian law) was administered by a hierarchy of officials. At the top stood the king. Only he could inflict capital punishment, or even corporal punishment (at least in theory). 


Below the king, the high priest of the Zoroastrian church was the most senior judge in the land. Beneath him, eminent spiritual leaders had wide judicial powers, especially when it came to trial by ordeals. They also had authority to interpret the Zoroastrian scriptures (the Avesta) in the application of law.


Below them a hierarchy of religious judges handled spiritual matters, widely defined to include family matters, contracts and so on.


The army and navy


The Achaemenid armed forces


The composition of the Achaemenid army changed over time. Under Cyrus all male Persians were required to fight in the army, and contingents of subject peoples were called up for specific campaigns. Darius created a standing army of professional troops, containing both horsemen and foot soldiers and all recruited from amongst the Persian and Iranians.


The backbone of the army was formed by an elite corps recruited from amongst the Persians and Medes. These acted as the royal guard, and were known to the Greeks as the 10,000 “Immortals”, but this may have been a mistranslation of the Persian word for “retainer”. Their commander was “second after the king” in the empire, and seems to have been responsible for all military matters.


Permanent garrisons were stationed throughout the empire at strategic points — along the frontier, or guarding main routes. These garrisons came under the control of the satraps of the provinces where they were stationed. They were often composed of troops from subject nationalities - Greeks, Carians, Chorasmians, Jews, for example. It seems that the garrison soldiers were allotted farmland from which to support themselves, either by farming it directly or renting it out. 


For campaigns the professional troops were supplemented by troops levied from all parts of the empire. In this way huge armies could be formed. These were divided into national units and armed according to their national customs. As time went by Achaemenid kings relied more and more on mercenaries, particularly for their infantry. The Greeks were by far the most highly regarded of these troops-for-pay, and played a major role in the wars of the later Achaemenid kings.


The fighting force of Persian armies on campaign were accompanied by siege trains and specialists in siege warfare, as well as well-organized logistic support. In these, the Persians were drawing on ancient experience in the Middle East going back to at least the time of the Assyrians.


The Persian navy was recruited and officered entirely by subject peoples with a seafaring tradition. the Phoenicians were the outstanding example of these, and the cities of Tyre and Sidon provided the bulk of the fleet.


Parthian and Sasanian military

The Parthians were the first to develop heavy cavalry, made possible by the breeding of sturdier horses. Both riders and horses wore chain armour. This force - the famous cataphracts - was recruited from the landed aristocracy, and was firmly under the control of the higher nobility. 


The Parthian army also had light cavalry, armed mainly with bows and who used highly effective “hit and run” tactics in battle.


The infantry was of much lower status than the cavalry, and of less tactical importance. It seems to have been composed mainly of feudal levies, peasants from the estates of the aristocracy.


The Sasanians’ army was similar to the Parthians’, but the heavy cavalry’s armour got heavier still: a Sasanian cavalryman was clad head to toe in chain mail, and his horse wore a long chain mail skirt down to his knees or lower. The success of this arm would force the Romans to raise similar forces and make the cavalry a much more important element within their own armies, downgrading their great infantry legions.