Paul D. Wilke
Why Justinian’s Wars Were Terrible for the Byzantine Empire
One wonders what Justinian did to provoke the venomous hit piece his historian Procopius wrote in the later years of his reign. By then, Procopius had penned eight volumes narrating Justinian's wars of conquest. These are remarkably detailed accounts of Justinian's wars in Italy, Africa, and Persia, and mostly depicted the regime in positive terms. Unlike most histories of the ancient world, Procopius was an eyewitness, taking part in many of the campaigns as a member of general Belisarius's staff.
Another book, The Secret History, was written for posterity and painted an entirely different portrait. It's clearly the work of a very disgruntled man. Noble Belisarius comes across as a weak cuck to his whoring wife. Justinian appears as a heartless monster and avaricious tyrant, indifferent to the suffering of his people, while queen Theodora was a shameless slut and schemer. Procopius clearly had an axe to grind. The Secret History is so black and riven with obvious exaggeration that historians today rightly find it hard to take too seriously, entertaining though it might be.
One consistent theme in The Secret History was how ruinous Justinian's wars had been for the empire. Writing in the 550s, he condemned these wars as the product of an "anthropomorphic demon." Procopius writes, "It would be easier to number all the grains of sand than those whom this emperor killed. Making a rough estimate of the lands that are now devoid of inhabitants, I would say that ten thousand time ten thousand times ten thousand died."  This was hyperbole, but there is a grain of truth here: Justinian's wars of conquest ultimately weakened his empire.
In this essay, I will argue that Justinian left the Byzantine empire strategically overstretched. This has long been the traditional view, though one that's recently been challenged. Revisionists argue that Justinian's conquests were not directly to blame for the losses after his death. Chris Wickham wrote, "Justinian's reign does not seem to have been a negative turning point for the empire."  Why? Because his successors seemed to have done well enough in holding off the empire's many enemies. Where they failed, Justinian was not to blame. Historian Peter Heather acknowledges the incredible human cost of Justinian's wars but concludes that we have no substantial evidence that his western expansion hurt the empire's security. 
I want to challenge these recent reinterpretations. I believe the traditional view holds true. Justinian's reconquest of the former Roman west was detrimental because it left the empire with an unresolvable strategic dilemma. What was that? Simply put, the creation of a sprawling third front in the western Mediterranean composed of Italy, Africa, and southern Spain, a geographic area not much smaller than the rest of the empire combined. The incredible burden of controlling this new front came in addition to and at the expense of maintaining security on the other two fronts.
Since the permanent split of the Roman Empire in AD 395, the Eastern Roman Empire (later the Byzantine empire) had two primary fronts to defend. One of those was the northern front in the Balkans, whose border followed the Danube River from west to east across Central Europe. This had been the Roman empire's northern border for over five hundred years, shielding its prosperous regions to the south along the Adriatic coast, Greece, Thrace, and Constantinople.
Two field armies, one in Illyricum, the other in Thrace, were dedicated to this front, though they were often badly under-resourced or diverted to serve on other fronts.  From the fifth century on, this region was plagued by barbarian incursions and sometimes full-scale migrations. By Justinian's time, the northern Balkans was impoverished and depopulated after a century of insecurity, though the southern coastal regions of Greece and along the Adriatic were doing better.
Next, the eastern front facing Persia was arguably even more important to the empire. It stretched from the southeastern coast of the Black Sea in the north to the Arabian desert in the south, protecting the empire's economic heartlands in Syria, Palestine, Asia Minor, and Egypt. While in the Balkans, the threats tended to be smaller barbarian bands, against Persia it was different. The two ancient rivals knew each other well, having fought off and on for the last three centuries. Wars, especially on the eastern front, were massive in scale and horribly costly for both sides. Even in peace, every wise Byzantine ruler understood the need to station a substantial force to guard the frontier and deter invasions.
Out in the western Mediterranean, Justinian's conquests created a new front that was to become a money pit for the empire during his life and after. Of the conquests, perhaps only Africa became an asset until it was lost to advancing Muslim armies in the seventh century. Spain was never really more than a distant outpost. Whatever prosperity Italy had at the start of Justinian's reign (thanks to decades of benign Gothic rule) was gone after two decades of bitter fighting. And for what? What did the empire gain from this? Prestige? A few beleaguered outposts in the western Mediterranean? The resources squandered in these western campaigns were not available for use on the other two fronts.
Simply put, Justinian is to blame for the empire's strategic overreach. He created this situation, taking a precarious but manageable two-front strategic model and transforming it into an unsustainable three-front version.
In fact, Justinian often stripped these core regions, especially the Balkans, to reinforce his struggling armies in Italy, Africa, and Persia. We can see the overstretch even before the bubonic plague ravaged the empire in 541-542. In other words, not even the singular event of the pandemic gets him off the hook.
It was a matter of time before the strain of juggling three fronts would prove too much. As we'll see, Byzantium only had sufficient resources to focus its main efforts on one front at a time, and its enemies knew this and took advantage. This was untenable in the long run. Justinian barely held it all together during his reign, but it all began to unravel after his death in 565, slowly at first, and then in an avalanche after 602.
Anastasius: Justinian Without All The Warmongering
It's worth taking a step back to see how the two-front system worked under an emperor who resembled Justinian in many ways. This was Anastasius (491-518), whose underrated influence is unfortunate. Both rulers had long, impactful reigns. Justinian governed for 38 years, Anastasius for 27, even though he took over when he was already 60. Both came to power after holding key high-level positions in the government, so they were experienced administrators who knew how to run an empire.
Both were ambitious reformers. Justinian famously revamped the legal code. He also ended payments to the border troops and used the money saved to increase the size of the professional field armies. Anastasius overhauled the financial system so efficiently that he left a substantial surplus in the treasury. He also tweaked army pay and the perks for military service to make it a more attractive career option. This apparently worked so well that he could fill the ranks with volunteers.
Historian Warren Treadgold writes, "The success of these fiscal reforms was swift, sweeping, and widely applauded. While modestly reducing taxation and maintaining spending, Anastasius rapidly filled the treasury. Taxpayers seem to have found payment in cash more convenient; the abolition of the quinquennial tax won universal approval in the cities, and the army's effectiveness soon improved." 
Anastasius presided over a mini-golden age. Eastern cities flourished after nearly a century of uninterrupted growth. By the sixth century, Constantinople had reached around 500,000, Antioch had 200,000, Alexandria around 100,000, and numerous cities like Jerusalem, Caesarea, and Ephesus dotted the landscape with populations between 50,000-100,000.  As Treadgold observes, "In fact, in the early sixth-century the empire appears to have been stronger and richer than at any time since the second century A.D." 
That's saying something, especially since the second century is widely regarded as the apogee of the Roman Empire, a true golden age that would not be seen again until the modern world. Much of this was thanks to Anastasius and his immediate predecessors. They had managed with great difficulty to navigate the empire through a series of internal and external crises in the fifth century. It had been a close call at times, but they made it, unlike their colleagues in the west. Justinian thus inherited a world others had painstakingly built for him. The empire was flourishing like it hadn't in centuries.
But we shouldn't let the similarities overshadow one crucial difference. Unlike Justinian, Anastasius didn't have imperial ambitions. He preferred peace though he wisely prepared for war. He understood the empire's two traditional fronts already presented enough challenges without going out and seeking others.
Persia, for example, was an empire of equal size that could levy massive field armies, conduct sophisticated military operations and besiege large cities just as well as its Byzantine rival. This made it a dangerous opponent. Anastasius understood that war with Persia was fraught with risk, tended to be horribly expensive, and rarely achieved anything lasting or decisive. He worked to maintain the long peace with Persia that had been such a boon for the empire during the otherwise turbulent fifth century. However, when war finally broke out, he was ready. In 502, the Persians attacked and won several early victories on the frontier. He then stress-tested his fiscal and military reforms under real-world conditions a year later. They worked well enough.
He marshaled an army of 52,000 men, far larger than any single army Justinian ever fielded. In the campaign that followed, the Byzantines, as usual, won some and lost some, but they held their own. For Anastasius, a tie was as good as a win. Most importantly, the show of force convinced the Persian King there was nothing more to be gained by fighting. In 504, the two empires signed a treaty that lasted over twenty years.
The northern front in the Balkans presented an entirely different set of challenges for Anastasius. Here, the Danube marked the traditional northern boundary of the empire. However, throughout the fifth century, the northern frontier's defenses collapsed several times, allowing barbarians to roam at will in the Balkan provinces. This was not an epoch when Roman armies wrapped themselves in glory. On the contrary. Most famously, the Visigoths annihilated the Eastern Roman field army at Adrianople in 378 and then pillaged their way through the Balkans for the next twenty years. The fifth century saw more of the same, but now it was the Huns cutting through Eastern Roman armies like soft feather pillows.
By Anastasius's time, the northern Balkan frontier was one of the poorest in the empire, so depopulated it could not even support the armies stationed there to defend the borders. Barbarians weren't the only concern. The Balkan field army was also a constant source of danger. Chronically underpaid, under-equipped, and ill-disciplined, it became a continual source of anxiety to Byzantine emperors, from Anastasius to Maurice (582-602).
Therefore, defending two fronts already stretched the empire's limited resources. Persia would always be a danger. The Balkans would constantly be threatened by some barbarian invader de jure, whether Visigoths, Huns, Gepids, Ostrogoths, Bulgars, Slavs, or Avars - the names changed every few years, but the precarious security situation didn't. The empire dealt with each new emerging threat the best it could, buying off some, paying others to attack mutual rivals, and only as a last resort sending in the army.
Nevertheless, Anastasius demonstrated that the state could navigate through a crisis and not break the bank. Unlike Justinian, peace was his preferred status quo, and his subjects should have thanked him for it. He largely kept the empire out of destructive and wasteful wars of choice and left it in far better shape than it had been since the early fourth century.
The contrast between Anastasius and Justinian is worth highlighting because it shows that the empire already had all it could handle defending two fronts. But it also shows what could be done with an able administrator who focused his efforts on improving government rather than chasing ephemeral dreams of renewed imperial splendor.
So let's take a moment to salute dull, old Anastasius. He wasn't a great general or conqueror, but he was a great emperor. Though largely forgotten now, and certainly overshadowed by his more famous successor, he nonetheless offers us a favorable alternative to Justinian's way of governing. His style was moderate; his wisdom and expertise understood the limits of the empire he ruled. Crucially, he wisely decided to stay within those bounds. Unlike Justinian, he left the empire stronger than he found it.
Justinian Creates the Western Front
Anastasius went to his well-deserved eternal rest at the age of 87 in 518. After the usual palace intrigue, Justin I (518-527), the commander of the palace guards, came out on top. He was already 70 and so elevated his nephew Justinian to co-rule the empire. He chose well. Justinian was intelligent, energetic, an able administrator, and a shrewd judge of talent. As Justin's health faltered, Justinian took over the day-to-day running of the empire. Think of Justin's reign as little more than a ten-year transition from Anastasius to Justinian.
After Justin's death, the first crisis was a war with Persia after two decades of peace. But Justinian had several things working in his favor. First, thanks to Anastasius, he'd inherited a fiscally sound government, a full treasury, and a competent, professional army. He also had Belisarius, arguably one of the most gifted generals of late antiquity. As was often the case, this war followed roughly the same pattern: the Byzantines won some victories, and the Persians won some too, even handing Belisarius a rare battlefield defeat before the war settled into the usual stalemate of siege and counter siege.
In 531, the Persian King Khavad died and his successor, Khosrow (531-579), needed peace to consolidate his power. Justinian also wanted peace so he could focus his efforts elsewhere. And so the two empires signed an "Eternal Peace" in 532, which stipulated that the Byzantines send Persia eleven thousand pounds of gold a year. To compensate for this loss in money, Justinian simply didn't pay the troops on the Persian frontier for a year.  Not paying the troops, or deferring payment until they rebelled, became a recurring theme of Justinian's reign, and after as well.
So far, all of this was manageable when only dealing with two military fronts. By 532, Justinian had peace on the northern and eastern fronts. Anastasius would have used such a calm interlude to recoup the state's coffers and fortify any weak spots. Justinian chose to go another direction, instead deciding to launch his wars of conquest in the western Mediterranean.
Beginning in 533 with his invasion of Vandal-controlled Africa, down to the last years of his reign in the 560s, any recuperating interludes of peace would become rare. The empire was at war almost constantly for the next two decades. Here was the new three-front reality.
But I'm getting ahead of myself. In the 530s, things were still looking up. The early years saw a stunning series of victories that overshadowed the gross incompetence underlying the whole enterprise. In 533, Belisarius attacked the Vandals in North Africa, one of the former Western Roman Empire's wealthiest provinces. In a lightning campaign, he ended the Vandal kingdom after two decisive battles. Right after that, he took Sicily from the Ostrogoths with minimal effort. And just like that, within a year, the Byzantines had North Africa and Sicily back in the imperial fold.
Sensing he had the momentum, Justinian decided to keep going since his eastern and northern fronts were still quiet. Meanwhile, he had a veteran field army led by a military genius on the western front. Why not go for the grand prize of the ancient Roman heartland in Italy? There would never be a better chance than now. In 535, Belisarius landed in southern Italy hoping to replicate the success he'd had so far in Africa and Sicily.
Unfortunately, Justinian had given him a laughably small force to wage the campaign. This was the first in a series of terrible decisions that would turn the war into a twenty-year quagmire. Yet Belisarius did what he did best: win. He made the most of what his stingy master gave him. Even so, the early fighting was ominously more difficult than expected.
Far from welcoming the Byzantines as Roman liberators saving them from the humiliating barbarian yoke, the native Romans had accommodated themselves to the relatively benevolent rule of the Ostrogoths. The Ostrogoths, especially under the Romanopile Theodoric the Great (493-526), had broadly respected Roman traditions. What most people don't know is that peace and prosperity returned to the peninsula after the chaotic collapse of Roman power in the fifth century.
By 540, after several years of hard fighting against the Ostrogoths, Belisarius had pacified most of the Italian peninsula. He ended the war by a deceptive stratagem. When the desperate Goths offered Belisarius their crown to turn against Justinian, he appeared to accept the offer to rule as their king. Believing they had their new leader under Belisarius, the Ostrogoths opened the gates of Ravenna and let him and his army in. It was all a ruse.
Belisarius captured the Ostrogothic leader, Wittigis, and the Gothic treasury too, all of which were shipped back to the capital for display in an epic triumph. This was all very clever on the part of Belisarius and added immensely to his legend (and Justinian's simmering jealousy), though the deception soon had repercussions. He'd ended the war, won Italy, and captured the Gothic king and his treasury. Not too bad.
Here I want to pause a minute to survey the situation. By 540, Justinian's new western front appeared secure. Italy, Sicily, and North Africa were back within the imperial orbit. Sure, some unrest in Africa was becoming a drag on resources – not paying your occupying troops will do that, but it was nothing that threatened Byzantine control. And sure, the Ostrogoths were seething when they found out they had been duped, but they were scattered, leaderless, and demoralized. They weren't seen as a threat anymore.
Imperial administrators arrived in Italy to reintegrate it into the empire's tax structure. There was a lot of work ahead, but the hard fighting was done, or so it seemed. Justinian had restored large tracts of the former Western Roman Empire. It was quite an accomplishment.
Yes, it's true the empire now had three fronts to defend, but that seemed very manageable in 540. The empire's armies had repeatedly proven themselves qualitatively and quantitatively superior to their western rivals. Justinian had captured the Vandals and Ostrogoths' treasuries, so he was flush with cash, at least for the moment.
Now roll the credits and everyone lived happily ever after.
But not so fast.
Appearances are deceptive. The empire would soon begin hemorrhaging money and manpower through non-stop, high-intensity warfare, first on one front, then another, and then another, and back again to the first, defending territories that eventually spanned from southern Spain to Mesopotamia. True, sometimes there were windfalls, as when Belisarius captured the Vandal and Ostrogothic treasuries. But as the years pass, we see the strain begin to show. More was going out than coming in. A lot more. The initiative held by the Byzantines in the 530s shifted in the 540s. Then they constantly found themselves reacting to a never-ending stream of crises.
And let's be honest, something that's often overlooked is that many of Justinian's decisions were just plain terrible. As mentioned before, he didn't pay the troops on the Persian front for a year to make up for the subsidy he'd paid the Persian king. He expected newly-conquered Africa to pay for itself almost immediately and so didn't pay the soldiers until they revolted. Right after winning Italy for the first time, he sent Alexander, nicknamed "the Scissors" for his parsimony, to Italy to extract as much wealth as possible. This alienated the soldiers stationed there since they were not exempt from his extreme cost-saving measures.  His failure to pay the troops in Italy on time provoked Rome's garrison to twice betray the city to the Goths. 
He expected Belisarius to conquer Italy with half as many men as he had for Africa.  If he was trying to cut costs, it backfired spectacularly, adding another fifteen years to a conflict that should have been over. Another reason the Italian campaign dragged on for so long was Justinian's consistently delinquent payments to the soldiers (see a pattern?), so much so that they mutinied and went over to the Goths numerous times . The momentum the Byzantines had enjoyed since 533 began to reverse, and this happened even before the plague struck in 541.
The Strain & Drain of Justinian's Reign - Juggling Three Fronts
A pattern began to emerge beginning in 539. It went something like this: a military crisis on one front was addressed at the expense of the security on the other two fronts. Justinian consistently shifted forces from one region (or both) to meet threats in another. This became obvious to all, especially his enemies, who were keen to exploit any weakness on their frontiers.
For example, by 539, Justinian had stripped the Balkan armies to reinforce Belisarius in Italy.  What happened next? The Bulgars attacked, breaking through the diminished defenses along the lower Danube and pouring into the soft and squishy Byzantine hinterlands. One group made it as far as the suburbs of Constantinople. Another penetrated south into Greece. Altogether, the raiders captured thirty-two forts and went home laden with plunder and 120,000 prisoners. Though they didn't take any major cities, they left the countryside devastated wherever they went. Most notably, we hear little about any effective defense. Apparently, there wasn't any. 
We also have evidence Justinian transferred forces on the eastern front for action in Italy. As in the Balkans, weakness invited attack, in this case from the Persians. Khosrow had been approached by Gothic emissaries who warned him that Persia would be next if the Goths were defeated.  Remember that involuntary pay holiday Justinian had inflicted on the soldiers so he could pay Persia the gold demanded in the terms of the "Eternal Peace"? Well, Khosrow probably remembered as well and gambled that what forces opposed him in the east were few, far between, and suffering from low morale.  It was a safe gamble.
When Khosrow realized his neighbor was heavily committed in distant Italy, he conducted his own lightning campaign in Syria in 540. Once again, Byzantine resistance ranged between feeble and non-existent. This time, Khosrow advanced all the way to the Mediterranean coast and sacked Antioch, the third largest city in the empire. This was a massive blow to the Byzantines and Justinian's prestige.
But that was it. This was just a quick grab-and-go offensive by Khosrow, who decided to quit while he was ahead and retreat back into Persia before Justinian could respond. Like the Bulgars a year before, Khosrow sauntered home unscathed but now he was the one laden with Byzantine plunder and prisoners. Both the Bulgar and Persian raids can be seen as opportunistic attacks in response to provocative weakness, a weakness created by Justinian's third front.
Do you see the pattern? But wait, there's yet another link in this sequence of events. Thinking the war with the Ostrogoths was over, Justinian sent Belisarius and the bulk of the Italian field army east to deal (belatedly) with the Persian attack. Of course, this left Italy vulnerable at a difficult time. You see, it turns out those seething Goths still had a lot of fight left in them. They'd found a new leader in Totila, who would prove a match for Belisarius in the coming years.
The reality of Justinian's overextension was just beginning to emerge at this time. Some argue that the empire might have been strong enough to overcome these challenges but for one unforeseen calamity: the arrival of the bubonic plague.  This completely changed the equation, they argue. That's partly true, but it ignores the fact that the aggressive foreign policy Justinian imposed on the empire seven years earlier was showing signs of floundering even before the plague arrived. One thing is true: The plague removed any doubt about whether Justinian had overextended the empire. He had.
"During these times there was a pestilence, by which the whole human race came near to being annihilated" (Procopius Wars II.XXII)
We know the plague arrived at the Egyptian port of Pelusium in 541 and then spread throughout the Mediterranean.  The disease reached Constantinople in March 542 and began killing people by the thousands every day. At its peak, the authorities struggled to dispose of the bodies, stacking them like firewood in make-shift mass graves or cramming them in vacant defensive towers. The stench of death overwhelmed the city. Procopius was not far off when he claimed the pestilence came near eradicating all of mankind. It must have seemed that way in 542.
The overall mortality rate after this first wave is a source of contention. The maximalist view argues that around 50% of the empire's population died from the plague.  This estimate has a scientific foundation since we now know the nature of the bacterium (Y. pestis) and the mortality rate it caused in more recent circumstances. Another line of thinking argues for a far lower death count, that the plague was not nearly as disruptive as the maximalists would have us believe. 
It's beyond the scope of this essay to examine the evidence one way or another. Whether 50%, or far lower, there is a broad consensus the plague and its aftershocks remained a drag on the Byzantine economy long after the initial wave passed. The empire's expenses didn't change though its tax revenues fell due to the plague. Justinian refused to relent. Kyle Harper writes that "By the middle of his reign, the empire was probably charging the highest tax rate ever imposed in Roman history."  Even worse, whatever demographic recovery the empire began to make after the first wave was interrupted by subsequent waves in 558, 573, 586, 599, 698, and 747. 
Post Plague (AD 542-565) - Same Strategy, Fewer Resources
Somehow the Byzantines picked up the pieces and moved on. We can see the plague's lasting impact on Justinian's ability to recruit soldiers and collect taxes to pay those soldiers (however tardily).  However, the fact he found ways to recruit large armies implies that the mortality rates might have been debilitating, but not catastrophic, for the empire.
And keep in mind, this was in the post-plague world that supposedly killed 50% of the population. I think we can be skeptical of the higher estimates while not downplaying the impact of the plague on Byzantine society. That was real. In the years immediately after the plague, we see attempts by the government to cut costs to reflect the reduced tax base. During this period, Justinian simply stopped paying the border troops, using the savings from that to maintain the professional field armies and wage the ongoing wars against the Persians and Goths. 
In any case, Justinian stayed the course, fighting on multiple fronts in the 540s and early 550s, with the emphasis given to the western front in Italy. There, Totila's rebellion gained so much momentum that the Byzantines were dragged into a fifteen-year war of attrition that was only won when Justinian finally committed the resources to overwhelm his dogged opponents. While grinding out the win in Italy, Justinian took the opportunity to divert some of his forces to capture southern Spain from the Visigoths.
Meanwhile, war with Persia continued fitfully until 562, though most of the fighting after 554 centered on control of Lazica. Once again, all of this happened post-plague, hinting at the resilience of Byzantium's economy and the limited impact of the plague.
But still, the strategic dilemma of the new three-front reality remained. In fact, it was exacerbated by the damage wrought by the plague. While the northern front in the Balkans was tranquil during the crisis years in the 540s, we hear of another dangerous raid in 558 that threatened the capital itself.
The historian Agathias, who took up the narrative of Justinian's later years where Procopius left off, remarks how poor the security situation was in the Balkans by the late 550s.
"The Roman armies had not in fact remained at the desired level attained by the earlier Emperors but had dwindled to a fraction of what they had been and were no longer adequate to the requirements of a vast empire"  (Agathias 5.13.7-18).
This time, three war bands consisting of Bulgars, Slavs, and Kotrigur Huns invaded the Balkans. The Huns defeated a Byzantine army and dashed for the defenseless capital. Belisarius, now retired, cobbled together a scratch force of volunteers, guardsmen, and war vets living in Constantinople that managed to ambush and force the Huns to retreat (Agathias 5.14-25).
The immediate threat passed, but it again highlighted the precarious situation in the Balkans. Agathias says that the Balkans' defense had been neglected for so long that they were all but non-existent by this time (Agathias 5.14.3-5).
The Byzantines might temporarily buy off barbarian threats around the Danube. This strategy often worked quite well to keep the peace, and it was one Justinian deployed quite skillfully. But when it didn't work, they were subjected to devastating incursions on its already-war-torn northern front.
The last years of Justinian's reign were largely peaceful, an anomaly from the previous thirty years. The war in Italy was over. The Byzantines and Persians squabbled over client states in the Caucasus, but no major wars took place on the eastern front. After the raid in 558, the northern front was relatively quiet.
Finally, the Byzantines could use the peace to recoup losses and consolidate their gains, as Anastasius had before. But that wasn't going to happen. Byzantium's enemies wouldn't let it catch its breath and consolidate those gains.
Justinian's Legacy - What he left behind
After Justinian, we see his successors struggling to maintain the empire's integrity across three sprawling fronts. Could it have worked if the plague had not sapped the empire's strength? Probably not. There's evidence that poor policy rather than a lack of money created the most problems in the immediate years after his death.
Justin II (565-574/8) was the first up. His lavish spending at the start of his reign, partly to help consolidate his shaky hold on power, shows that the empire still had some money, perhaps due to the peace dividend in the last years of Justinian's reign. Justin's extravagant spending also hints at how unpopular Justinian's draconian fiscal policies had been, especially among the aristocracy, who were the most common targets of his cash-hunting expeditions. One of the first things Justin did was cancel all tax arrears up to 560. Large donatives were given to the people and he paid back loans Justinian had forced the rich to make to the state. Though short-sighted, this was quite popular after getting fleeced by Justinian's officials for the past three decades. 
However, the foreign policy woes began soon after Justin took power. He probably wished he had that money back he'd just given away. Justin was quickly forced to confront Justinian's legacy of the three-front dilemma: too many fronts, too few troops, and not enough money. In a terrible lapse of judgment, Justin decided to forego paying the Avars an annual subsidy. Justin felt this was beneath Roman dignity, though it had been common practice before and would be again.
The Avars were the most recent arrivals to the Danube frontier. In the coming decades, they would prove to be Byzantium's most dangerous Balkan foe. Predictably, the offended Avars attacked and caused immense destruction. As usual, the understaffed Balkan field army's performance was underwhelming. 
Then, in 567, the Visigoths attacked Byzantine holdings in southern Spain, taking Cordoba. Justin could do little about it. Why? Because he had an even bigger calamity breaking out in Italy. A year later, in 568, the Lombards invaded Italy and occupied most of the peninsula outside a few major cities. This would be permanent. The depleted Army of Italy put up a pathetic resistance. And just like that, Byzantine Italy was reduced to a few outposts on the coast, including Rome, Naples, and Ravenna. In Africa, the Moorish king Garmul invaded the province and killed the Byzantine prefect, Theodore.
None of these crises motivated Justin to send reinforcements. Indeed, he probably couldn't. His initial spending spree to buy the people's goodwill left him short of cash to defend his frontiers. New taxes were imposed on bread and wine to compensate, which burned away whatever fickle goodwill he'd won initially without really allowing him to win anything back. It was already too late for that.
It got worse. Justin simply let the western front fend for itself. Instead, he foolishly provoked war with Persia, something he'd dearly regret. After a few minor victories, the Persians counterattacked and took Dara, the hinge of the empire's frontier defense. The sources tell us that the loss so shook Justin that he reportedly went mad, so much so that his attendants had to take precautions to keep him from jumping out of the windows. 
We hear from John of Ephesus that Crazy Justin enjoyed nothing more during his last years than to be pulled around the palace in a little wagon like a child.
"The most successful of these was a little wagon, with a throne upon it for him to sit upon, and having placed him on it, his chamberlains drew him about, and ran with him backwards and forwards for a long time, while he, in delight and admiration at their speed, desisted from many of his absurdities" 
Such was the caliber of the man who inherited Justinian's empire.
Tiberios II (574-582) stepped into the breach and attempted to retrieve the situation. He reversed Justin's policy with the Avars and agreed to pay them a hefty sum of eighty thousand nomismata per year for an alliance. In return, the Avars would defend the Byzantine frontier on the Danube while Tiberios sent forces from the Balkans to fight the Persians. This had predictable results.
In 577, around a hundred thousand Slavs moved into Thrace and Illyricum, where they meant to settle down. This was no mere raid like before, but a full migration. The Avars broke the peace in 579 and attacked Sirmium (located in northern Serbia). As usual, the Balkan army was unable to cope. To cap it all off, the army on the eastern front facing Persia was threatening to mutiny because their pay was overdue. 
Tied up in Persia, the Byzantines had no answer for these Slav and Avar attacks. Tiberios did the best he could but the crises kept coming from all three fronts. His short reign would see the empire's fortunes fall even further. The war with Persia continued while the Lombards nibbled away at the remaining Byzantine possessions in Italy, and the Slavs and Avars preyed upon the undefended Balkans. This was the three-front model in practice.
Maurice took over in 582 and reigned competently and attentively for twenty years. His reign was characterized by constant fighting and a never-ending shortage of cash. And this was no meek palace emperor, either. Maurice often led Byzantine field armies on campaign for the first time since Theodosius the Great (379-395). He did better than anyone could have expected, though in the end it was too much, even for him. Of the three immediate successors to Justinian, Maurice came the closest to making the three front reality work.
That even an able leader like him failed shows how unworkable Justinian's three-front empire had turned out to be. With little margin for error and covering three fronts that demanded constant attention, bad leaders like Justin worsened the situation. In contrast, good leaders like Maurice were constantly scrambling from crisis to crisis, forever forced to economize and cut costs to an ever-more dangerous extent. There's something about Maurice's reign that evokes the image of a man moving about desperately trying to patch leaks on a storm-battered and slowly sinking ship.
In any event, he almost pulled it off. Maurice managed to finally get a favorable peace with Persia in 591 after his timely aid helped a Persian claimant to the throne gain power. The grateful winner, Khusrow II, ceded significant territories along the border to the Byzantines.
However, by the later years of Maurice's reign (582-602), the constant lack of money was impossible to ignore, forcing him to make ever more dangerous compromises regarding army pay. Justinian had set a dangerous precedent. He got away with frequently not paying his troops, or delaying payments to the point of mutiny. Maurice became a reminder of how dangerous such a policy could be. It would cost him his life. But not quite yet.
By the 580s, hordes of Slavs and Avars had settled in large portions of the northern Balkans. Maurice finally made the region a priority after signing a peace treaty with Persia in 591. He tried to restore the situation in the Balkans and even had some success by the end of the 590s. Unfortunately, the region had been neglected for far too long for any quick fixes. The Balkan field army was disgruntled and mutinous and became even more so because of Maurice's persistent and tone-deaf cost-saving measures.
One of those measures was to have the army spend the winter living off the land north of the Danube in enemy territory. It had been standard practice for the army to return to winter quarters within the empire's borders, where soldiers could spend time with their families and enjoy regular life. Maurice barely survived his first attempt in 593 to implement this policy. Only the prudent, but dangerous, decision of the Balkan army commander to countermand the emperor's order prevented a full scale rebellion. Maurice apparently learned nothing from this close call and tried it again in 602. This time the army rebelled, marched on Constantinople, and murdered Maurice. 
Lesson learned, though a bit too late.
Here began the terrible seventh century for the Byzantines. Justinian's western conquests were left to fend for themselves. Africa did OK until the 680s when Islamic armies conquered them. What little that was left of Byzantine Spain quietly ceased to be in the 620s when the Visigoths took advantage of the empire's weakness to capture the few remaining towns.
A few Byzantine outposts like Rome and Ravenna survived on a peninsula now otherwise ruled by the Lombards. Persia overran much of the middle east by 620, conquering Syria, Palestine, parts of Asia Minor, and Egypt before Heraclius launched his remarkable counteroffensive that completely defeated the Persian empire and deposed its king. But that's a story I've told elsewhere.
Justinian was a man. Men are mortal. Therefore Justinian was mortal. This little bit of elementary logic is key to understanding why his three-front model was untenable. Let's accept for the moment that he was a remarkably talented ruler and a skilled administrator with a shrewd eye for identifying talent. Let's also assume for the moment that by the end of his reign, he had managed to hold it all together, though just barely. All this despite a crushing tax burden, one of the worst pandemics in history, and a never-ending stream of predatory enemies trying to pick away at the empire.
But Justinian was mortal. He wasn't going to live forever, though it must have seemed so to his long-overtaxed subjects. For the three-front model to be viable, it needed a built-in margin of error to account for the random wide distribution of talent you find in an absolute monarchy as the Byzantines had. As we've seen, the men who followed Justinian were not up to the task.
Poor Justin II just wanted to make everyone happy, spending lavishly before wasting his final years racing around the palace in his little throne-mounted wagon. He was a decent man, but a mediocrity who was in way over his head. Tiberios II was too. Only Maurice was worthy of his predecessor's inheritance but by then it was probably too late. As the years passed after 565, Byzantium's enemies sensed weakness and began chipping away at Justinian's conquests, taking most of Italy, much of Spain, and wreaking havoc in Africa. Not even noble Maurice could stem the tide for long.
Justinian's successors were caught in a dilemma. The only way to fund this enlarged empire would have been by maintaining his punitive revenue collection practices. Perhaps this would have provided the money to meet the challenges. But then again, maintaining the status quo would have created dangerous unrest for any newly-minted sovereign with a precarious perch on the throne. All that pent-up discontent might threaten to explode with revolts and insurrections. Justin II and Tiberios both tried dialing back on the taxes to head this off. It seemed to work. The people applauded these moves.
But buying domestic stability came at the cost of the empire's security. It really was zero sum. In addition, war became the norm soon after Justinian's death, and constant warfare kept the imperial coffers from recovering. Maurice managed to juggle all these balls for twenty years but even he, one of the more gifted emperors in Byzantine history, eventually paid with his life for skimping on army pay. He was, after all, only following the dangerous precedent already set by Justinian: i.e., to save money, don't pay the troops.
In the end, the empire was simply too big to govern a territory spanning the Mediterranean. Yes, the plague of 541 and the recurring outbreaks sapped the empire's demographic and economic strength, but not drastically enough to account for the empire's losses after 565. Of course, it didn't all fall apart immediately after Justinian. I would say two words describe the Byzantines throughout their long history: resilient and tenacious.
The decades after Justinian's death would be no different. The Byzantines fought hard to hold what they had. Even so, an undeniable decline happened before the great collapse of the early seventh century. I am convinced the exhausting strain of trying to keep Justinian's empire together set the stage for the calamities that befell the empire after Maurice's death in 602. There is indeed a connection.
In retrospect, the dull but pragmatic governance of Anastasius offered a more sustainable model for the empire. He had no reckless imperial ambitions. He wisely paid his soldiers, made service more attractive, and lowered the tax rates for the people while not harming the state's revenues. He left the treasury full of gold and his empire in excellent health.
Justinian did not, though his story is so much more interesting to tell.
Rise and ruin tales always are.
(1) Procopius. The Secret History with Related Texts. Translated by Kaldellēs Antōnios Emm, (II.18.4-5), Hackett, 2010.
(2) Wickham, Chris. The Inheritance of Rome: Illuminating the Dark Ages, 400-1000, Penguin Books, New York, 2010, p. 94.
(3) Heather, Peter. Rome Resurgent: War and Empire in the Age of Justinian, Oxford University Press, New York, 2018, p. 329.
(4) Treadgold, Donald Warren. History of Byzantine State and Society, Stanford University Press, Stanford (California), 1997, pp. 244–246.
(5) Ibid., 168.
(6) Ibid., 275.
(7) Ibid., 182.
(8) S., Evans J A. The Age of Justinian?: The Circumstances of Imperial Power, Routledge, London, 2000, pp. 153–154.
(9) Treadgold, 207.
(10) Ibid., 189.
(11) Heather, 264-265.
(12) Whitby, Michael. “Chapter 8: The Balkans.” The Wars of Justinian, Kindle ed., Pen Et Sword Military, Yorkshire ; Philadelphia, 2021, p. 6081.
(13) Heather, 281.
(14) Procopius. History of the Wars Books I and II, II.II, Bibliobazaar, London, 2007, pp. 121–122.
(15) Greatrex , Geoffrey, and Samuel N. C. Lieu. “The Roman Eastern Frontier and the Persian Wars AD 363-628.” ProQuest, Routledge, 23 Sept. 2008, p. 102. https://ebookcentral.proquest.com/lib/apus/detail.action?docID=240585.
(16) Luttwak, Edward N. “The Emergence of the New Strategy.” The Grand Strategy of the Byzantine Empire, Belknap Press of Harvard University Press, Cambridge, 2011, pp. 85–86.
(17) Procopius. History of the Wars Books I and II, II.XXII, Bibliobazaar, London, 2007, pp. 191-193.
(18) Harper, Kyle. “The Wine-Press of Wrath.” The Fate of Rome: Climate, Disease, and the End of an Empire, Princeton University Press, Princeton, NJ, 2019, pp. 244–245.
(19) Mordechai L, Eisenberg M, Newfield TP, Izdebski A, Kay JE, Poinar H. The Justinianic Plague: An inconsequential pandemic? Proc Natl Acad Sci U S A. 2019 Dec 17;116(51):25546-25554. doi: 10.1073/pnas.1903797116. Epub 2019 Dec 2. PMID: 31792176; PMCID: PMC6926030.
(20) Harper, Kyle, pp. 234–235.
(21) Harper, 237.
(22) Laiou, Angeliki E., and Cecile Morrison. The Byzantine Economy (Cambridge Medieval Texts). Cambridge University Press, 2007, Kindle ebook, Accessed 2 Oct. 2022.
(23) Treadgold, 199.
(24) Agathias. The Histories, De Gruyter, Inc., 1975. ProQuest Ebook Central, https://ebookcentral.proquest.com/lib/apus/detail.action?docID=935878.
(25) Treadgold, 219.
(26) Ibid., 220-221.
(27) Ibid., 223-224.
(28) Ephesus, John of. John of Ephesus, Ecclesiastical History, Part 3 -- Book 3, https://www.tertullian.org/fathers/ephesus_3_book3.htm.
(29) Treadgold, 225-226.
(30) Haldon, John. Warfare, State and Society in the Byzantine World 560-1204, Taylor & Francis Group, 1999. ProQuest Ebook Central, p. 29. https://ebookcentral.proquest.com/lib/apus/detail.action?docID=167326.
(31) Norway, John J. “Imperial Parsimony.” Byzantium: The Early Centuries, Knopf, New York, 1989, pp. 274–275.
(32) Laiou, Angeliki E., and Cecile Morrison. The Byzantine Economy.
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