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  • James Houser

December 12, 627 - The Byzantine-Sassanid War, the "Dark Ages' World War II"

Updated: Jun 17, 2021

December 12, 627 AD. The final showdown is here. For over 25 years, the two greatest empires of the civilized world – the Byzantine Empire and the Sassanid Persian Empire – have been locked in an apocalyptic struggle for survival. Today, the Byzantine Emperor Heraclius finally defeats his foes for good near the ruined city of Nineveh. It is the end to the epic conflict of the age, the Dark Ages’ World War II – but the real nemesis of both empires is just beginning to emerge.

In the year 600, it seemed like the opposite would happen. For the first time in four centuries, the Emperors of Rome and the Shahanshah of Persia had a lasting peace built on a mutual friendship that stood a good chance of surviving whatever came its way. The two empires that together dominated the civilized world from Rome to the borders of India had also forged an alliance to assist each other in time of attack. Had the alliance held up, things would have been much different – as we will see. But in 600, that seemed to be the way things were going.

The Byzantine Empire was led by the Emperor Maurice, an excellent military organizer and strategic mind. Maurice had inherited a sprawling, powerful empire that had extensive territories in Spain, North Africa, and Italy along with the heartlands of Greece, Anatolia, Egypt and the Near East. The Byzantine Empire was also the bastion of Orthodox Christianity, then far more prominent and successful than its weak competitors to the west, like the still-minor Bishop of Rome, only now beginning to be called “papa,” or Pope. The icons and mosaics of Orthodox culture adorned the metropolis and capital of the Empire: Constantinople, the Christian Rome, the greatest city in the world. Even though the Western Empire had fallen in the 470s, the Eastern Empire remained vibrant and strong.

The Sassanid Empire was an altogether different beast. The Persian lands had come under many different ethnic groups – Greeks, Scythians, Parthians - since the glory days of Cyrus, Darius and Xerxes, but the Sassanids were ethnic Persians for a change. Persian culture was blossoming, and the Sassanid Shahanshahs (the word literally meaning “King of Kings”) explicitly sought to resurrect the past glory of the ancient Persian Empire, once destroyed by Alexander.

Instead of Christianity, the Sassanids followed the faith of Zoroastrianism, a mystical faith that aligned the light god Ahura Mazda against the darkness of Ahriman. Their mountaintop temples, attended by cliques of holy men, held the eternally burning flames of Ahura Mazda proudly. The Persians ruled modern Iraq, Iran, the Caucasus, and much of Central Asia – not the rich lands of the Byzantines, but a stronger base than it appeared. Their capital was the great city of Ctesiphon, about 22 miles south of modern Baghdad. It was the only rival to Constantinople as the great metropolis of the age.

The Roman and Sassanid Empires had been locked in border wars for centuries, usually along the perpetual fault lines of the Caucasus and the Jazira. The Jazira is a stretch of desert near the modern Syrian-Iraqi border, and ever since the 100s AD Persia and Rome had been fighting over the border forts and towns that made up this military frontier. Many a fierce war had been waged between the two empires that ended with nothing more than a few cities being traded one way or another. The Romans had occasionally penetrated into Iraq to attack Ctesiphon, and on a couple of expeditions the Persians had gotten into inner Syria, but never did they get farther. The terrain was punishing, wars were extremely expensive, and both empires were just too powerful and resilient to do much more to each other. Stalemates had been the name of the game for almost five centuries, and it boggled the mind to consider what might happen if that were to change.

One such war took place between the Byzantines and Sassanids from 572 to 591, just the usual donnybrook. Pro-Byzantine uprisings occurred in Armenian Christian sectors of the Persian-ruled Caucasus territories, and the Byzantines came to help their co-religionists. The fighting continued for a while, with neither side really able to gain an advantage, until suddenly in 589 a new development occurred. The Sassanid Shahanshah, Hormizd IV, was deposed and killed by one of his successful generals, Bahram Chobin. He was allegedly strangled to death with his own turban. The dead king’s son, the crown prince Khosrow, took the major step of fleeing – to the Byzantines. He begged the Emperor Maurice for help to regain his throne. Maurice agreed, on the condition that the Byzantines regain their border cities.

Maurice sent his armies to Khosrow’s assistance, and by 591 he was in power as Khosrow II, King of Kings. Khosrow was prepared to be a different kind of Shah: he showed tolerance to Christians, remained close with Maurice, and even may have married Maurice’s daughter Maria. Khosrow’s reign saw the full flower of Persian revival culture, including a renaissance in music, literature, and art. Most notably, the Byzantine-Persian frontier was at peace, and the two empires were cooperated to resolve their mutual differences. Khosrow was a man of honor, and he felt heavily indebted to Maurice for the favor and good will he had shown him in his moment of need, so he treasured the relationship with his new ally and vowed to keep the peace as long as possible.

But Maurice wasn’t going to live forever. In fact, he wasn’t really going to live that long. The extended borders of the Empire cost great sums of money to maintain, and the treasury had been in dire straits ever since Emperor Justinian’s campaigns of conquest in the 530s. To keep his finances afloat, Maurice was forced to cut his soldiers’ pay and the pensions of his generals. While this was a necessary move, no political leader ever gets rewarded for cutting the military, especially not in ancient times when the military might have something to say about it. In 602, a disaffected general named Phocas revolted against Maurice and captured Constantinople; the Emperor tried to escape but was soon captured and put to death, along with all six of his sons. Phocas crowned himself as the new Emperor.

Maurice is a relatively rare example of a strong, competent, popular ruler being overthrown and killed, and his murder rent the Byzantine Empire into competing factions. But none would be as problematic as the man MOST upset by Maurice’s death. This was Khosrow, King of Kings, who was enraged by his father-in-law’s betrayal and execution. Ultimately, he had been allied and favorable towards Maurice, not the Byzantine Empire as a whole, and now that his friendly ally was gone, he saw an excuse to attack. So was Khosrow upset about Maurice’s deposal, or did he just want to attack the Byzantines? Probably a bit of both. In 602, the Sassanid Empire invaded the border once again. No one knew it yet, but the truly great, apocalyptic deathmatch between the two empires had begun.

As the Persians came crashing over the border, the new Emperor Phocas was facing a crisis. Many of the Byzantine governors and generals throughout the diverse empire refused to recognize the new ruler, and long-simmering religious divisions burst to the fore. Christianity was still a very new faith in the Byzantine Empire, relatively speaking, and there were still doctrinal and spiritual differences between numerous sects. The Miaphysite faiths of the Coptic, Armenian and Syriac Churches opposed the supremacy of Constantinople in the Orthodox Church, and their adherents in Syria and Egypt had never been content under Imperial authority.

As generals went into rebellion and cities into riot across the Empire against the murderous regime of Phocas, the Sassanids found themselves pushing at an open door. Soon the border cities and forts had fallen. ALL of them. The Persian armies were advancing into Roman imperial territories that they had not seen for centuries, and the Romans were still too busy fighting each other to oppose them. The Persians overran Edessa, Armenia and Aleppo, and launched raids deep into Turkey and the Syrian farmlands. To make matters worse for the Romans, a tribal group known as the Avars swept through the Empire on the European front, raiding into Greece and the Balkans. It seemed like crisis was breaking out everywhere.

In the midst of this chaos, an opposition figure finally stepped forward to oppose Phocas. His name was Heraclius, the son of the Exarch of Africa (aka modern Tunisia), and his family had been loyal subordinates of the murdered Maurice. In 610, as the Persians were continuing to barrel into Byzantine territory, Heraclius led a fleet to Constantinople. Upon the arrival of the young (35), handsome, and brilliant challenger, the population of the great city rose up and helped him overthrow Phocas, who was swiftly executed. Heraclius was now proclaimed emperor, and given the task of somehow stopping the Persian advance.

If Khosrow had really been invading to avenge his dead father-in-law and benefactor, he should have been satisfied now: Phocas was dead, and Maurice was avenged. But by now Khosrow had a different vision. The unexpected ease and rapidity of the last eight years of conquest had conjured an altogether different vision. With the glory of Persia in both military strength and cultural supremacy obviously on the rise, why not keep pressing? Was not now the time to reclaim the mantle of Cyrus and Darius? Would there ever be a better opportunity to rebuild the Persian Empire of old? He would continue his attacks.

Heraclius tried to rally his armies and march them to the border, but the Byzantine armies had been ruined by poor pay, bad leadership, corruption, and the cruel hand of Phocas. They could offer only halfhearted resistance, no matter what the status of their leadership. The Persians beat them in every fight, even when their new and vigorous emperor was at their head. City after city fell. In 611, the great Syrian city of Antioch fell into Persian hands, and in 613 Damascus suffered the same fate. Now the Byzantine Empire was split in two, with all land communication with Egypt and Palestine cut off, and the Byzantine army was unravelling. The Persians turned their sights on the most prestigious prize of all.

In 614 AD, the Persians marched south, accepting the meek surrender of city after city. The citizens negotiated with their conquerors rather than fight against this seemingly unstoppable foe. Finally, after three weeks of siege, the holy city of Jerusalem fell to the Persians. The sack was terrible, as Khosrow’s soldiers slaughtered almost 65,000 people and carted many prisoners off to Persia, including the Orthodox Patriarch. What struck the Byzantines in the heart, though, was the fate of Jerusalem’s Christian relics. Khosrow had all the churches and temples burned, including the Holy Sepulcher over Jesus’s purported crucifixion site, and took the relics of the True Cross and the Holy Lance back to Persia. It was as if the Sassanids had ripped the heart out of the early Christian faith. By 616, the Persians were overrunning Egypt, and were gearing up to march on Constantinople itself.

After the capture of Egypt, Khosrow sent his foe Heraclius a letter: “Khosrow, greatest of Gods, and master of the earth, to Heraclius, his vile and insensate slave. Why do you still refuse to submit to our rule, and call yourself a king? Have I not destroyed the Greeks? You say that you trust in your God. Why has he not delivered out of my hand Caesarea, Jerusalem, and Alexandria? And shall I not also destroy Constantinople? But I will pardon your faults if you submit to me, and come hither with your wife and children; and I will give you lands, vineyards, and olive groves, and look upon you with a kindly aspect. Do not deceive yourself with vain hope in that Christ, who was not able to save himself from the Jews, who killed him by nailing him to a cross. Even if you take refuge in the depths of the sea, I will stretch out my hand and take you, whether you will or no.”

To the Christians of the Byzantine Empire, it must have seemed like the end of days was truly upon them, and that seemed to be the spirit. Religious terror lanced across the Christian world at the terrible news. The Persians, with visions of world empire dancing in their eyes, had set out purposefully to destroy God’s Empire. It was Jesus versus Ahura Mazda to the Persians and the Byzantines. The war became not just a struggle between two countries, but a spiritual and apocalyptic tale, the great battle for survival. There was a very real risk that the Persians could destroy the last remnant of the Roman Empire, and it was up to Emperor Heraclius to keep that from happening.

As it turned out, Heraclius – and the people of the Byzantine Empire – were up to the challenge. In the face of apocalypse, they hunkered down and prepared for the endgame. Sergius, the Patriarch of Constantinople, donated all the money and resources of the Church. Constantinople was filled with patriotic demonstrations and religious processions, carrying relics and crosses throughout the streets. Heraclius cut the budget to the bone, halving the pay of government officials, forcing loans, and debasing the currency. All the gold and silver in Constantinople was ordered to be melted into coinage, which as usual carried the face of the Emperor Heraclius, but also contained an unusual slogan. The coins said “May God Help the Romans”, which sounds both desperate and resolved. If the Roman Empire was to die, it was to die fighting.

As the Persians advanced, Heraclius devised a desperate and bold strategy. He would take the main Byzantine field army – what was left of it – and use his control of the sea to launch an amphibious assault deep into Khosrow’s rear. But he wouldn’t try to hold cities or fortresses; instead, he would launch roving, constantly moving expeditions that would seek out and defeat Persian armies. When they weren’t fighting, they were training. Heraclius would avoid battle and engage in small skirmishes to build up his troops’ confidence and experience before fighting the Persians’ mighty horse archers and their fierce mailed cavalrymen. In the meantime, Constantinople would be left exposed – but they would have to do the best they could.

In 622, Heraclius launched his first campaign by landing near Syria and marching deep inland with around 50,000 men. He built up his army’s discipline and confidence over the summer, then pretended to retreat, drawing the Persians after him. At the Battle of Issus, he unexpectedly turned to fight, with the Byzantine scaled-armor spearmen and cataphract cavalry dealing a sharp blow to the Persians. Heraclius himself led the cavalry charges, his purple imperial regalia flowing around his golden armor. Issus was a minor victory, but Byzantine morale soared, and throughout the rest of the year Heraclius continued to win small battles before putting his army in winter quarters and returning to Constantinople to reorganize for next year. By the end of 622, the Byzantine army was full of piss and vinegar once again. Maybe they could really win this thing.

For the next several years, Heraclius followed this pattern. He would spend winter in Constantinople making arrangements, preparing the campaign plan, and seeing to political matters. Before winter was over, he would return to his veteran army encamped somewhere in Persian-occupied territory and go on another rampage. Heraclius wasn’t making short treks, either. By 623 he wasn’t just operating in former Byzantine lands, but penetrating deep into Persian territories. That year, his army nearly captured Khosrow, but did manage to capture and burn the shrine of Urmia. This was the purported birthplace of Zoroaster, the founder of the Sassanid religion, and long-savored payback for Jerusalem. In 624, Heraclius even made it as far inland as Teheran, as far as any Roman or Byzantine army had ever come into Persia. These epic treks spanned hundreds of miles, lasting months at a time, as Christ’s Emperor made his bold and slashing campaigns and won battle after battle.

By 626, Khosrow was fed up. The Persians had suffered many setbacks from this unexpected Byzantine resurgence, but it was time to end it. He gathered a truly massive army of almost 150,000 men, and split it three ways. One was to pin down Heraclius’s force in northeast Turkey, while the others were to launch a great assault on the walls of Constantinople. At the same time, Khosrow had allied with the Avars, who would encircle the city from the west. It was to be a pincer movement against the great city: the final attack that would destroy the Byzantine Empire. When these colossal armies lurched into motion, Heraclius reacted by sending 12,000 veterans to help defend Constantinople while maintaining a reactive defense in Turkey, forcing the Persians to worry about that flank. He could only hope that Constantinople would hold.

From June 29 to August 10, 626, the people of Constantinople rallied to defend the last city of the West. The Avars assaulted the walls time and again, while the Persians on the opposite bank of the Bosporus built small boats to try and cross the small bay. The battles were ferocious, with only 12,000 Byzantine soldiers available to fight off overwhelming numbers of Persians and Avars. Morale was incredibly high, though. The defenders were led by the Orthodox Patriarch Sergius, who led a daily procession around the walls with the icon of the Virgin Mary. Rumors of miracles, heavenly visions and divine intercession kept resistance alive, and the peasants of the city answered the Patriarch’s call to contribute their labor to rebuilding the walls. It was religious fervor that kept Constantinople alive in its dark hour, and after two major defeats by the Byzantine navy the invaders withdrew. The epic siege was over, and it seemed like the stormcloud of apocalypse had finally lifted. The tide had turned.

The disastrous siege of Constantinople, after five straight years of successful campaigns by Heraclius, caused many Persians to despair of ultimate victory. Some generals even began to change sides, or refuse to listen to the increasingly manic Khosrow, who could see his dream of triumph slipping away. This was no longer about Maurice, who had been dead for 25 years now, or about border forts. It was a fight to the finish, and Heraclius prepared his army. The Emperor now had an ace in the hole: he had allied with a distant tribal confederation known as the Turks, who would strike Persia far in the east near Afghanistan at the same time as Heraclius struck from the west. Together, they could finally bring the King of Kings to heel.

In 627, with 70,000 men, Heraclius landed on the Syrian coast again and advanced in force, reconquering almost all the fortresses and cities lost to the Byzantines so many years ago. The Persian army still facing Constantinople, suddenly cut off from its homeland, was forced to surrender, clearing Turkey of the invaders. Disaffected Persian generals in Egypt and Palestine laid down their arms as well. As Heraclius penetrated deep once again, Khosrow ordered his generals to make a fight of it in sight of the ancient ruins of Assyrian Nineveh. The field of battle would be Arbela, where Alexander had won his great victory over the Persian Empire 900 years ago. Here, at the Battle of Nineveh, the decisive clash of the last Roman-Persian War commenced.

The two armies squared off on December 12, 627. Though the Byzantines had superior armored infantry and heavy cataphract cavalry and the Persians superior horse and foot archers, they were imbalanced in other ways. The Persian general Rahzadh probably had a numerical superiority, but Heraclius had the morale advantage. In a hard-fought clash, Heraclius once again feigned retreat, then turned around to smash the disorganized Persians. Heraclius was in the thick of battle, and was wounded, but managed to corner and kill Rahzadh in one-on-one combat. By nightfall the Persians were completely smashed and in full-on retreat. Heraclius, unlike almost any other general of the age, ignored his own wounds and his army’s losses and launched an immediate pursuit. Right on the heels of the fleeing Khosrow, Heraclius’s troops stormed fort after fort before drawing up in front of the Sassanid capital of Ctesiphon. It had taken 26 years, with many ups and downs, but the war had come to this: from Byzantine disaster to their troops before the enemy’s capital.

Heraclius proposed peace. Khosrow refused, raging about the glories of the Persian Empire, but after 26 years of war the nobles of Persia had had enough. They deposed the unlucky Khosrow and installed his son Kavadh on the throne, and the new King of Kings immediately accepted Heraclius’ terms. Astonishingly, Heraclius proposed a return to the status quo – that is, if they Persians gave up all their conquests and restored the holy relics of Jerusalem, including the True Cross and the Spear of Destiny. The Persians almost fell over themselves to accept, including the payout of a large financial indemnity. After so much heartache and trial, the last Byzantine-Persian War was over.

Heraclius returned to a jubilant Constantinople, after restoring the True Cross to Jerusalem in an emotional ceremony. He had pulled off one of the greatest feats of arms in world history, taking a crumbling Byzantine Empire from imminent defeat to glorious victory. Had he died at that moment, as he marched in triumph through the greatest city on Earth, he would be ranked along Hannibal, Alexander or Caesar. He had led the Byzantine Empire through its darkest hour, and possibly saved the future of Christianity and the West in the process. The enormous scale and scope of the great Byzantine-Persian War really could have altered the course of history, and the fate of Western Christianity hung by the slimmest thread in 626 AD. In its scale, emotion, and epic stature, the Byzantine-Persian War was something like the Second World War of the Dark Ages.

But it was two fatally weakened, crippled empires that faced each other after the war was over. From Constantinople to inner Persia, from Egypt to Armenia, the land was ruined by massacre, looting, famine and war. The people had become disaffected from either empire, only wanting to live their lives in peace. Half the Byzantine Empire had lived under foreign occupation for a decade and resented the new taxes of the returning authority of the Emperor. Finally, both the Byzantine and Persian Empires were utterly ruined by the war, their treasuries depleted, armies exhausted and lands despoiled. The Persians had broken themselves trying to reclaim their old glory. The Byzantines had survived, but pulled out all the stops to do so and shot their last bolt. In their defense, they couldn’t have known what was coming.

In 629, as Heraclius restored the True Cross to Jerusalem, a religious hermit brought his followers into Mecca and began the military conquests that would shake the world. His name was Muhammad, and even before they could catch their breaths, the Byzantines and Persians faced a sudden onslaught from the desert. The human tsunami known as the Arabs poured out from the south, overrunning the Middle East and preaching the creed of Islam. The eastern provinces that Heraclius had fought so hard to recover – Egypt, Syria, Palestine – were lost one after another, never to be reconquered. The True Cross was lost to Byzantium forever.

But the Byzantine Empire got off easy: they survived. By the 640s, the Arabs had completely conquered Persia, and from here on out it would be a mixed Muslim-Persian legacy that would dominate Iran and Iraq. The Zoroastrians remain a religious minority to this day, but the future of Persia was no longer in their hands. The Sassanids were gone. Long live the Caliph.

The Great War of Persia and Rome had produced no winners, only losers. The real winners were the Muslims, and they would inherit the lands of both in the end: a tragic drama forgotten to mainstream history.

And this is my longest post ever! Congratulations to me, or not.

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