In 476 CE the western Roman Empire fell. For places like Britain, the fall of Rome meant the fall of civilisation and the beginning of a dark age (which you can read about in our article on the rise of the Anglo-Saxons here). However, far to the east, on the plains of Persia, a new golden age was about to dawn.
Foundation
In the early C3rd CE a new power arose in Persia. The old Parthian Empire, the great eastern rival of Imperial Rome, collapsed. In 224 at the Persian capital of Ctesiphon a new King of Kings (Shahanshah) claimed the throne. He was Ardashir I, the first ruler of a new dynasty, the Sassanids.
Ardashir soon made his presence felt across the east, raiding deep into the territories of Rome in 230. During the course of his reign he consolidated and expanded his Empire, adding the provinces of Sistan, Gorgan, Khorasan, Margiana, and Balkh, and the cities of Chorasmia, Bahrain, and Mosul. The kings of Kushan, Turan, and Mekran would all come to acknowledge him as overlord.
The Sassanid Dream
Ardashir was not simply building an empire, he was building a dream. It was a dream of restored Persian glory. A dream of building an empire every bit as glorious, powerful, and magnificent as the ancient Achaemenids. Before he died, he went to the trouble of writing a testament, addressed to his son, outlining his vision of the principles of empire. It covered ethics, doctrines of war and standards of good government. Ardashir’s was to prove an incredibly powerful political vision, one that would form the foundation of the Sassanid Empire for centuries to come.
Ardashir’s son, Shapur I, would prove every bit as capable as his father. He continued to expand the empire, adding new territories. Shapur conquered Bactria, as well as the western portion of the Kushan Empire, extending the eastern borders of the empire as far as India.
War with Rome, when it came, sent shock waves across the Roman world. In 260 CE, just outside Edessa, the unthinkable happened. Shapur defeated and captured the Roman emperor Valerian. Nothing like it had happened before in the history of Imperial Rome. The Romans now knew that their eastern rival was far more dangerous than the Parthians had ever been.
Rome’s Great Rival

Conflict with Rome would continue to erupt from time to time, sometimes favouring the Romans and sometimes Persia.
The Sassanid military, like the Parthians before them, remained primarily a cavalry army. Whilst many Sassanid horsemen were lightly armed, the empire was most famed for its heavily armed and armoured Cataphracts. Under the Sassanids the Cataphracts were trained in complex battlefield manoeuvres, co-ordinated by officers using whistles. During the period of late antiquity and the early Middle Ages, the Cataphracts probably represented the best quality heavy cavalry in the world.
Unlike the Parthians however, the Sassanids developed sophisticated siege warfare technology. They also provided their infantry with better equipment and at least some Sassanid infantry were as well armed and armoured as any of their Roman counterparts.
Siege technology
The Parthians had been unable to take well-defended Roman cities by siege. The Roman writer Cassius Dio noted their lack of siege equipment and their poor tactics. Speaking of one Parthian attack on a Roman fortification he observed:
“they found that they could not harm at all by their siege, but, on the contrary, as often as they tried conclusions with him, were repulsed by both the native troops and the Romans that were in his army”
Cassius Dio, Roman History, 62.20
Recent archaeology has shown that the Sassanid military were far more capable when it came to siege warfare. Excavations of the city of Dura-Europos, besieged by Shapur I in 256 CE, revealed the extent of this sophistication. Dr Simon James concluded that the Sassanids:
“…were a match for their Roman enemies in terms of military technology and engineering expertise. Both sides shared a wide range of pre-gun-powder military equipment and combat methods, some of which–as in the case of the use of gases and smoke in the mines–they had both inherited from the Greeks, others which they learned from each other.”
Dr Simon James
Empire
The fact that most sources for the history of the Sassanid Empire are Roman tends to provide us with a ‘western centric’ view of events. However, it is important to acknowledge that the empire also had southern and eastern borders that played a key role in Sassanid history.
Control of the Persian Gulf was vitally important, due to the wealth it brought to the empire via sea trade. Arab pirates and raiding arab tribes represented a real threat. To combat this the Sassanids would create and maintain a strong naval presence. Over time this allowed them to gradually secure control of the gulf and its lucrative sea trade routes to India and southeast Asia.
In the east, trade via the silk roads and via the South China seas represented a great source of wealth for the Sassanids. The empire would build on earlier Parthian trading relations with China to greatly expand its east asian markets. By the C5th, Sassanid merchants visited with such frequency that they established formal diplomatic relations with the Chinese Emperor. They bought silk from China of course, but they also sold carpets, textiles, furniture, leather, pearls and gourmet delicacies. They even introduced Persian music and dance to the Chinese. Large quantities of Sassanid coins give testimony to the extent of this trade (most dating from the fourth to the seventh century). Persian coinage has been found in several Chinese cities, especially along China’s southern coast.
Within Persia itself, the empire experienced substantial growth in terms of urbanisation, agricultural production, economic activity, and population.
During the period of late antiquity and the early Middle Ages, at a time when much of the Roman world was in decline, Sassanid civilisation flourished.
New Challenges
The C4th brought with it new challenges. Rome remained the empire’s major rival in the west. However, it was in the east that a new and dangerous enemy was emerging. From around 370 CE, a wave of hostile tribes plagued the empire’s eastern provinces. These tribes overran Bactria and even threatened their Indian territories.
These invaders were a mix of Hunish peoples; Kidarites, Alchon Huns and Hephthalites (also known as the White Huns). Just as the Huns came to threaten the stability of the Roman Empire, they also posed a serious danger for the Sassanids.
Another challenge was a new religion – Christianity. The Sassanids were Zoroastrians and found the spread of this new faith every bit as disturbing as the Romans had done. Different Sassanid kings responded differently. Some aggressively persecuted the Christians; others were more tolerant. Naturally enough, anti-Christian persecutions would further strain relations with Rome once Constantine formally adopted Christianity as a state religion.
Bahram V
For a time, the Sassanids appeared to weather the storm of changing times. In 422 Bahram V made peace with Rome which allowed him to turn his attentions to the deteriorating situation in the east. He prosecuted a successful war against the Kidar Huns, that re-secured the silk road. To celebrate, he erected a pillar at the Oxus, to mark his empire’s eastern frontier, on the border of what is now modern Uzbekistan.
Bahram’s reign was not only successful in military terms. It was also a time in which Persian culture flourished. Some of the best literature and music produced by the Sassanids can be dated to his reign. He was also a great patron of polo, adopting the sport as a favoured royal pastime.
Bahram’s son, Yazdegerd II, continued to steer Persia through the troubled world of the C5th with reasonable success. However, when Yazdegerd died, in 457, the situation rapidly deteriorated.
An Empire on the brink
The late C5th saw the fall of the western Roman Empire. Far to the east, Sassanid Persia would face its own crisis.
Yazdegerd died without naming a successor and, inevitably, civil war ensued. His eldest son, Hormizd III, claimed the throne. So too did Hormizd’s brother, Peroz I, dividing the Empire. After two years of fighting Peroz emerged victorious but his troubles were far from over.

Peroz suffered a catastrophic defeat at the hands of the White Huns in 483. The Huns spent the next two years plundering the eastern provinces of the empire at will. Several major eastern cities fell before the attacks stopped. A peace of sorts followed but the Huns would continue to exact heavy tributes from the Sassanids for some years to come.
Peroz’s successor, his brother Balash, hardly enjoyed better success. The White Hun threat may have abated for now, but Balash soon faced other problems. His failure to bring Armenia to heel forced him to accept a highly unpopular peace. The nobility were outraged and Balash was deposed.
It was 488. Far to the west, Rome had fallen. In the east the Sassanid Empire looked weak, destabilised by civil wars, palace coups and the threat of the White Huns. Many wondered at the time whether this empire too was on the brink of collapse.
Back from the Brink
Peroz’s son, Kavad, was now raised to the throne. He was just 15. However, Kavad would prove to be an energic and determined leader. During his long reign he introduced reforms and re-built his royal authority over the nobility. It was no easy task.
Kavad used the dualist Mazdakite sect to counterbalance and undermine the power of the traditional Zoroastrian clergy and various powerful nobles. He also took on and eventually executed Sukhra, a Sassanian nobleman who had acted as a kingmaker during the reign of his father and uncle.
Kavad did not have it all his own way, however. He was himself deposed by the nobility and replaced by his more malleable brother, Jamasp, in 496. Kavad was imprisoned but somehow managed to escape (some stories say he escaped disguised as a woman). He fled east and eventually found sanctuary with the White Huns.
Kavad had little choice but to broker an alliance with the Huns. There would be a price to pay but only the Huns could now provide him with an army capable of taking back his crown. After two years of fighting Kavad was returned to power.
Kavad was firmly back in control, but he had only been able to achieve this with the backing of the White Huns. There was no denying the weakness of the empire. Kavad knew that only drastic change could hope to restore it to its former glory. And so he set about instituting a major programme of reform, covering everything from the tax system to the organisation of the army.
At the time of his death, it was an undeniable fact that Kavad left the empire stronger than he found it. However, he was never able to truly free it from the yoke of the White Huns.
The Immortal Soul

Kavad’s son, Khosrow I, became King in 531. Known as Khosrow with the immortal soul, his reign would witness a new Golden Age in Sassanid Persia.
Khosrow continued and built on his father’s reforms. He also set about dealing with potential internal rivals, taking advantage of a peace with the Byzantine Empire that was to last until 540. However, after this time, conflict with Byzantine would flare up again, on and off, for the rest of his reign. Overall, these wars were largely indecisive, but generally bought Khosrow’s regime more by way of successes than failure.
However, Khosrow’s military achievements in the east would ultimately prove far more significant.
Far to the east the old Rouran Khaganate was suddenly overthrown by their former vassals – the Turks. In its place, the First Turkic Khaganate rose to become the dominant central asian power. As the Turks began to extend their influence westward, this brought them increasing into conflict with the White Huns.
Khosrow saw his opportunity and forged an alliance with the Turks. The allies agreed to carve up the empire of the White Huns between them by launching a two-pronged attack. The Turks would attack from the east, whilst the Sassanids attacked from the west.
The end came at the Battle of Gol-Zarriun, fought in present day Uzbekistan, in 560. The combined Sassanid-Turkish forces decisively defeated the White Huns. Over the next few years, the fate of the White Huns was sealed. After this time, they divided into a number of smaller successor kingdoms and were never again powerful enough to seriously threaten the Sassanids. The old eastern imperial border at the Oxus was re-established.
A Persian Golden Age
The C6th would see Sassanid culture and civilisation reach its zenith under the reigns of Kavad I and Khosrow I.
Khosrow’s reign in particular saw many significant building projects in the form of bridges, roads, dams and walls. Perhaps most impressive was his construction of defensive walls on the empire’s eastern frontier. The Great Wall of Gorgon spanned the gap between the eastern coast of the Caspian Sea and the mountains in northeast Iran. The wall ran for a total of 195 km and included over 30 fortresses; the most extensive defensive wall ever built aside from the Great Wall of China.

One of the most impressive structures that survives from the ancient Sassanid capital of Ctesiphon is a great archway known as the Taq Kasra. It is not certain when it was originally built. Some date its construction to the reign of Shapur in the mid-third century but others believe it was constructed by Khosrow I in the sixth. Even today, this magnificent structure is the second largest single-span vault of unreinforced brickwork in the world after the Gavmishan Bridge (which was also built by the Sassanids).
An age of learning
Under Khosrow, Persia became an impressive centre for philosophy and learning. Neo-Platonists fleeing from the Byzantine Empire were welcomed with open arms. Khosrow encouraged the translation of a wide range of learned texts from different cultures, everything from Greek to Sanskrit and Syriac into Middle Persian. Intellectual games such as chess (introduced to Persia from India) and backgammon became the height of fashion. Khosrow was also a great patron of indian philosophy, science, mathematics, and medicine. This fusion of greek and indian knowledge led to the creation of the first hospital in the world that separated patients into different wards based on pathology.
Centres of science and learning such as the Academy of Gondishapur, were greatly expanded at this time. In the sixth century the Academy became the premier centre of science and learning in the world, promoting the study of everything from philosophy to medicine, physics, poetry, rhetoric, and astronomy. Much of what the Arabs were later to achieve in terms of their knowledge of mathematics and medicine, had its roots in Gondishapur.
Final Flowering
In the end the immortal soul did not live forever. His final years had seen a renewal of conflict with the Byzantine Empire but, when he finally died in 579, he left behind him a Sassanid Empire at the height of its power.
Khosrow II (591-628) is often considered to be the last great Sassanid King. Early in his reign he had to contend with civil war and was effectively deposed by a rebellious general, Bahram Chobin. Khosrow fled to the Byzantine Empire where he struck a deal with the Byzantine Emperor Maurice. He agreed to cede control of Lazitan and four contested cities to the Byzantine Empire, if Maurice could help him regain his throne.
Khosrow was restored to power by a combined Sassanid-Byzantine army forcing Bahram Chobin to flee and seek sanctuary with the Turks. Bahram Chobin was too dangerous to be left alive, so Khosrow bribed a number of Turkish nobles to arrange his assassination.
Good relations with the Byzantine Emperor Maurice allowed the two empires to live at peace with each other for the first decade of Khosrow’s reign. However, in 602 the Byzantine Empire was plunged into turmoil when Maurice was assassinated, and his throne usurped by his General Phocus.
Bloody conflict
Khosrow used the assassination as an excuse to declare war against the Byzantine Empire. In the bloody conflict that ensued, Khosrow grabbed Byzantine territory claiming that he intended to place Maurice’s son on the Byzantine throne. The Byzantines, divided by internal disagreements and under pressure from Avars and Slavs, rapidly lost ground.

By 621 the Sassanids had overrun most of the Byzantine Empire. Khrosrow had succeeded in fulfilling the dream of Ardashir; the ancient boundaries of the great Achaemenid Persian Empire were restored. For a time, it even looked as if greater glories were to come. Many wondering whether Constantinople itself might fall.
Decline
However, from 622 onwards the Byzantine Emperor Heraclitus was able to stage an effective recovery. By seeking out clever alliances with rebellious Sassanid nobles and with the Turks in the east he turned the tide against Khosrow. The decisive blow came at the battle of Nineveh in Mesopotamia in 627 when the Sassanid army was comprehensively defeated.
A palace coup quickly followed and Khosrow II was deposed. One of Khosrow II’s sons assumed the throne taking the name Kavad II. However, the new king quickly proved himself to be a blood-thirsty tyrant. Kavad proceeded to have not only his father, but most of his family and several other Sassanid nobles executed. It was an extreme, blood-crazed, attempt to eliminate all possible future rivals.
Kavad was able to make peace with the Byzantines but his violent tyrannical tendencies led to civil war. Kavad himself died of plague after ruling for only a few months, leaving behind him an empire in chaos.
Several kings followed in quick succession between 628 and 632 before Yazdegerd III was final chosen as king. However, at the age of just eight, Yazdegerd was no more than a figurehead. Real power lay in the hands of a mix of senior nobles and army commanders.
Neighbouring enemies soon sought to take advantage of the situation and the empire suffered a series of invasions by Turks in the east and Khazars in the west.
The Rise of Islam
The Sassanids, weakened as they were by civil wars and by their long war with the Byzantine Empire, were in no position to resist the oncoming storm that was about to break in 633.
Hostile arab tribes had threatened the empire’s southern borders many times before. But this time it would be different. In 633 an arab army invaded the empire united by the zealous belief in a new religion – Islam.
Khalid ibn al-Walid’s Muslim army defeated the Sassanids four times during April and May 633. His campaign culminated with the capture of Al-Hirah, the capital of Iraq, by the end of May.
It was the beginning of the end. From this time onwards the empire found itself increasingly overwhelmed by the islamic invaders. Yet, divided and weakened as they were, the Sassanids were still able to resist conquest for a few years.
The End of a Dream
The final chapter of the Sassanids would be played out following a crushing defeat at the hands of the Arabs at the Battle of al-Qadisiyyah in 636. The defeat left the way open for the muslim army to besiege the capital Ctesiphon. After two months, the capital fell in 637.
The Persians continued to resist, falling back to the east to raise new armies. But that resistance was becoming increasingly desperate. A last-ditch attempt to recover the empire was made at the end of 641/early 642. The Sassanids mustered their remaining strength for a final decisive battle at Nahavand.
The conditions seemed to favour the Sassanids. They were able to entrench themselves in good defensive positions and the initial arab attacks failed. However, the muslim army feigned retreat, enticing the Sassanids to leave their defences in pursuit. Lured into rough terrain in mountain gorges, the last great Sassanid army was massacred.
After the battle, Yazdegerd III fled, hoping to raise another army in the eastern provinces or, perhaps, broker an alliance with the Turks. He even sent an envoy to China seeking aid from the Tang emperor. But the eastern provinces were in no mood to provoke a confrontation with the victorious Arabs.
Yazdegerd’s attempts to raise a new army now represented nothing but a dangerous provocation that ran the risk of bringing ruin to the east. The end came in Marw, in modern Turkmenistan. Here, Yazdegerd was assassinated by a local miller in 651. The motive for the assassination is unclear, perhaps the miller had been hired by a nobleman, or perhaps he’d simply murdered Yazdegerd for his jewellery. Whatever the motive, the Sassanid Empire and the dream of Ardashir had finally died.
Keep up to date with our stories
If you like reading our work and would like to keep up to date with the latest stories and news from our blog page, you can follow us on Facebook. We always announce any news and promote new stories as they are published here:
https://www.facebook.com/MedievalHistorian
References and further reading
Archaeology of the Sasanian Empire, January 2012
Sasanian Persia: Between Rome and the Steppes of Eurasia (Edinburgh Studies in Ancient Persia)
Weapons and warfare – the Sassanids
Wikipedia – The Sassanid Empire
Images
Portrait of Ardashir – Mohammed Rasoulipour (Wiki Commons)
White Huns – Hunadam (Wiki Commons)
Cataphract – John Tremelling (Wiki Commons)
Silver Plate of Khosrow – Cabinet des Medailles (Wiki Commons)
Arch of Ctesiphon – Karl Oppolzer (Wiki Commons)
Map of the Sassanid Empire – Arab League (Wiki Commons)