Roman/Byzantine history is not exactly our main focus around here, so this post may seem a little out of left field. But the Byzantine Emperor Heraclius (d. 641) is actually a reasonably important figure in early Islamic history. Without Heraclius, the world in which Muhammad began preaching might have looked considerably different than it actually looked. In addition, he’s actually the subject of a legend surrounding Muhammad’s time as a preacher and as the leader of the budding Islamic community.
In 610 the Byzantine Empire was reeling, and things were only getting worse. Back in 602, then-Emperor Maurice had decided that the empire’s military expenses were too damn high, and his solution to that problem was to tell his large army campaigning against the Avars in the Balkans that it was basically on its own for the winter. This was a bad idea, and by the time that army had fully expressed just how bad an idea it was, Maurice was dead and a junior officer in the Balkan army, Phocas, was your new emperor. The problem for Phocas is that hardly anybody in the empire, aside from the army that had put him there, really approved of him taking the throne. One Byzantine governor in northern Mesopotamia, Narces, squatted in the northern Mesopotamian (today the site is in Turkey) city of Edessa, declared his independence, and begged Sasanian (Persian) Emperor Khosrow II for help in holding off Phocas’s inevitable attack.
Looping in the Persians had long been the nuclear option for any rebelling Roman/Byzantine governor or high official, but it was particularly so at this point in imperial history. After grappling with Germanic threats in Europe on equal or even disadvantageous military terms for centuries, by the time of Justinian (early 6th century) the Romans/Byzantines were once again the military power in their own backyard. They’d managed to reestablish military superiority by professionalizing their army (soldiers who do nothing but train to be better soldiers are unsurprisingly usually better at soldiering than amateurs) and by employing tactics borrowed from the dominant European power of the two previous centuries, the Huns. And mercenaries, too, don’t forget the mercenaries. And so only true military threat to the empire at this point was Persia, another large empire that also had a professional army that also used, and had defended against, tactics similar to those used by the Huns. So for Narces to appeal for Persian aid was a big deal.
Would he get it? Well, it so happens that the Sasanians and Byzantines had just ended a war in 591 on Byzantine terms (most of the Caucasus came under Byzantine control or “influence” as a result). That war had ended when Maurice helped Khosrow take his throne back from the (brief–he ruled for about a year) usurper Bahram VI. So not only were the Sasanians itching for a rematch, but Khosrow had particular reason to be indebted to Maurice and therefore hostile to the guy who’d had Maurice deposed and executed. He jumped at the chance to help Narces, and his armies defeated the Byzantines at Edessa and, in 605, at Dara (also in northern Mesopotamia/modern Turkey), which the Persians took for themselves. Narces then tried to patch things up with Phocas, but after being promised safe passage to Constantinople he was arrested and burned at the stake for his troubles.
People took things like promises of safe passage pretty seriously back then (it was hard to conduct diplomacy, trade, or really anything else if you thought the emperor might just snatch you up and burn you to death for kicks), so Phocas’s treatment of Narces didn’t do much for his already poor reputation throughout most of the empire. The Exarch of Africa (a very autonomous viceroy who ruled everything from southern Spain to western Libya in the name of the emperor in Constantinople) was a man named Heraclius the Elder, and in 608 he started minting coins (always a bad sign for imperial unity) declaring that he and his son, our Heraclius, were consuls.
The two consular offices were purely ceremonial positions by this time in Roman/Byzantine history, with no real authority, but it was the emperor’s prerogative to fill those offices. By declaring themselves consuls, the Heraclii were also more or less declaring that Phocas was illegitimate. Revolts began breaking out all over the empire, and Phocas was clearly incapable of dealing with them. Heraclius the Elder apparently died sometime around 610 (we don’t know exactly when), after his rebellion had captured Egypt. But his son, the younger Heraclius, sailed a fleet into Constantinople in that same year, and by that point things were so bad for Phocas that his own nobles basically handed him over to Heraclius for execution (which he’s said to have done personally, on the spot, when Phocas unwisely decided to mouth off to him).
Things got a lot worse under Heraclius before they got better, because the war with the Persians went against Constantinople for another 12 years. Khosrow’s armies swept through Syria in 611-613, defeating an army that Heraclius sent against them, then took Jerusalem in 614 and Egypt in 618. In every one of these places the Persians were not seriously opposed (though to be fair you can’t say they were exactly welcomed either) by the locals, who practiced various non-Chalcedonian forms of Christianity (Nestorianism, miaphysitism, etc.) and had generally (there were occasional respites) been badly treated by the Chalcedonian imperial center for some time. And this is to say nothing of the empire’s Jews, many of whom happily aided the Persians and did some terrible things to their Christian neighbors–who also, it must be said, had done some terrible things to them. By the early 620s, Persian armies were threatening to break into the Byzantines’ Anatolian heartland and were even within striking distance of Constantinople.
However, Heraclius bought himself a little time by agreeing to a heavily lopsided peace deal with Khosrow. He used that time to reorganize and rebuild his shattered army by debasing the currency, slashing all non-military expenditures to the bone, and partnering with the Church to cast the war with the Persians as a holy enterprise. In 622, Heraclius led his new, fairly small (probably about 25,000 but maybe as many as 40,000 men) army on an end-around invasion of the Persian Empire. He first drove the Persian army out of Anatolia but was then forced to return west to fend off those pesky Avars. The advance resumed in 624 though Armenia and south toward the Persian capital at Ctesiphon. He defeated no fewer than three separate Persian armies over the next two years.
It was at this point that Khosrow, perhaps a little concerned over this sudden Byzantine resurgence, made the mistake that would cost him the war, his empire, and his life. Uh, spoiler alert. He recruited two new armies and put them under the command of his two senior generals, Shahin and Shahrbaraz. The former he tasked with defeating or at least slowing down Heraclius, while the latter slipped past the Byzantine army and headed to Chalcedon, which the Persians had captured while Phocas was still around and which was practically within shouting distance of Constantinople. From there they moved to besiege the Byzantine capital. A diplomatic outreach to the Avars brought them as well as several Slavic tribes into the siege from the European side of the Bosphorus.
The siege began in earnest in late June 626 and lasted for about a month, but the sturdy Theodosian Walls held and the Byzantine navy was able to prevent the Persians and the Avars from coordinating their efforts (which rendered the Avars particularly ineffective as they were inexperienced at siege warfare). The destruction of both the Persian and Avar-Slav fleets broke the siege and ended the threat to the city. Khosrow was discredited by the failure and knives started coming out for him among the Persian nobility. Then Heraclius sent Shahrbaraz what he alleged were authentic letters, intercepted by the Byzantines, in which Khosrow ordered his general’s execution. Whether these were genuine or not, Shahrbaraz believed them and moved his army back into Syria and just stayed there, out of the fight.
While the siege was going on, Heraclius formed an alliance with the Turkic Khazars and decided to march on the Persian capital, Ctesiphon. The Khazars eventually turned back as they found the Mesopotamian climate unpleasant, but Heraclius pressed on and badly defeated an outnumbered Persian army at Nineveh in December 627. The war, for all intents and purposes, was over. There was no Persian army left to oppose the Byzantine invaders. Khosrow fled his capital for his fortress at Dastagird just north of the city. He planned to continue the fight, but his army, his nobles, and at least one of his sons had other ideas. In late February, Khosrow’s son Sheroe, with the backing of the Sasanian nobility and what was left of the imperial army, undertook a coup, and removed his father from power. Assuming the regal name Kavadh II, he quickly moved to execute all of Khosrow’s other sons while tossing Khosrow himself him down a hole for five days before executing him.
The Sasanians’ problems were only just beginning, but for Heraclius, whose army must have been past the point of exhaustion, the war had to end. He asked for fairly light terms considering the situation–mostly the return of the captured Byzantine territories as well as some relics that the Persians had carted off from Jerusalem, and reparations–and that was that. This returned the world to what amounted to the status quo ante bellum, and crucially it’s that world–one with two war-weary and weakened (by plague as well as war) superpowers having just pounded each other senseless to very little actual effect–into which Islam began to spread. History might have gone quite differently if the early Arab armies hadn’t started their march out of Arabia in the aftermath of the 602-628 war, when the great powers of the region were as vulnerable as they’d perhaps ever been.
Heraclius reigned until 641, which meant that he was alive (and well-known to the Arabs) during Muhammad’s lifetime and was also alive to see most of his empire lost to the Arabs after the Battle of Yarmouk in 636. He led the empire through one of its greatest victories and watched, almost helplessly, as it suffered one of its greatest defeats. There are a couple of Muslim tales relating to Heraclius that are worth mentioning. The first comes straight out of the Qurʾan itself. The thirtieth chapter is called Surat al-Rum, or “Chapter of the Romans,” and verses 2-4 read like this:
2. The Romans have been defeated,
3. In the nearer land (Syria, Iraq, Jordan, and Palestine), and they, after their defeat, will be victorious,
4. Within three to nine years. The decision of the matter, before and after (these events) is only with Allah, (before the defeat of Romans by the Persians, and after, i.e. the defeat of the Persians by the Romans). And on that Day, the believers (i.e. Muslims) will rejoice (at the victory given by Allah to the Romans against the Persians),
This is taken as a prophetic statement, since Muhammad preached it at Mecca, before his 622 flight to Medina and thus before Heraclius turned the war around (starting, coincidentally, in 622), and since it probably refers, in the “have been defeated” verse, to the Persian capture of Jerusalem in 614 (614 to 622 is “within three to nine years”). It’s meant to reassure the listener that monotheism would triumph over polytheism (the Meccans probably didn’t have a great understanding of Zoroastrianism and at any rate it wasn’t an Abrahamic religion), and hearkens to a time when “Islam” wasn’t yet a fully fleshed-out religion and it was possible for Muhammad’s followers to view the Christian Byzantine Empire as the good guys.
Heraclius himself is the protagonist, of sorts, of a story about Muhammad’s time in Medina. Some later Islamic historians/writers/fabulists claimed that, during his lifetime, Muhammad wrote to all the major world leaders of his day to tell them of his revelation and of the new faith, Islam. Heraclius, alone among all those leaders, is said in these stories to have recognized that Muhammad was the “messenger” who was supposedly foretold in a couple of esoteric passages in the Christian scriptures, for example John 14:16 and Acts 7:37. Heraclius then is supposed to have proclaimed Islam to his people as the One True Religion, at which point they practically revolted and Heraclius had to back down and pretend that he was “just testing their faith.”
Obviously this is a legend meant to enhance Muhammad’s stature by giving him the Byzantine emperor’s seal of approval. If Heraclius knew anything about early Islam (which many modern scholars don’t even think had coalesced into what we think of as “Islam” by the time Heraclius died), he probably thought it was a Christian heretical movement or a militant Jewish sect. It’s also intended to help explain why God allowed the Arabs to totally obliterate the Persian Empire (in the story, Khosrow reacts very negatively to Muhammad’s letter) while the Byzantine Empire, albeit a vastly shrunken Byzantine Empire, continued to exist–because while the Persians had rejected Muhammad thoroughly, in the Byzantine case at least their emperor had seen the light.