The Avars became a massive headache for the Byzantine Greeks—and for good reasons. Credit: Greek Reporter archive
Imagine being in Constantinople in the summer of 626 AD, when an Avar army is camped outside the Byzantine city’s walls. Across the Bosphorus, Persian forces are massing on the Asian shore. On the Golden Horn, a fleet of Slavic canoes is preparing to ferry troops across the water and link the two armies together.
Inside the city, the emperor is not even there. He is deep in Persian territory on a desperate counter-offensive, and the garrison is getting thin. By any reasonable measure, the empire should have collapsed that summer. Today, we know that it didn’t and that the Avars never recovered from the attempt, but this is the hinge on which one of early medieval history’s most consequential and least appreciated relationships turned. For the better part of a century, the Avar Khaganate and Byzantine Empire (also known as the Eastern Roman Empire) were locked in escalating violence, which led to an eventual catastrophe that permanently rewrote the map of southeastern Europe, including that of modern Greece.
Who were the Avars, who almost destroyed the Byzantine Empire?
The Avars did not come out of nowhere, but their precise origins remain genuinely contested among scholars to this day. The most widely accepted view links them to the Rouran confederacy. This was a powerful steppe empire in Central Asia that collapsed under Göktürk pressure in the mid-sixth century. The Göktürks were another nomadic confederation in medieval Inner Asia that established the first unified empire of Turkic-speaking peoples.
Fleeing westwards, the Avars swept across the Pontic grasslands, scattering or absorbing peoples in their path, and by 567 AD, they had planted themselves in the Carpathian Basin, the broad Hungarian plain that would remain the heart of their empire for the next two and a half centuries.
What they built there was the Khaganate, a genuine imperial structure, with the Khagan at its top and a complex hierarchy of subordinate peoples, including neighboring Slavs, Gepids, and remnant Germanic groups, beneath him. Militarily, they were innovative and very dangerous. They are widely credited with introducing the iron stirrup to Europe, a development that changed cavalry warfare on the continent. They also brought sophisticated siege expertise that most steppe peoples lacked entirely, which made them a different kind of threat to settled civilization than Europe had faced before.
This map illustrates the territorial reach of the Avar Khaganate across Central and Eastern Europe during its peak. Credit: Wario2, Wikimedia Commons, CC BY-SA 4.0
The turbulent relations between the Byzantines and the Avars
When the Avars first stood on the doorsteps of the Byzantine Empire under Justinian I, the empire’s response was well-calculated. Constantinople was deep in its exhausting double commitment of reconquering the western Mediterranean while fighting the perpetual war against Sasanian Persia on the eastern frontier. The north and the Danube were a problem that nobody had the troops to fully solve. Paying the Avars to go away, or better yet, to fight other troublesome peoples on Byzantium’s behalf, was simply cheaper than the alternative of trying to crash them militarily.
The arrangement that followed had a certain logic. The Avars were initially useful, helping to drive the Lombards out of Pannonia and into Italy in 568, tidying up one frontier problem even as they created the conditions for another. However, this transactional relationship between the Byzantine Empire and the Avars has its own momentum. Annual payments of gold signal to the recipient that the payer is either wealthy enough to afford it or weak enough to require it—often both—and the Khagans drew the obvious conclusions soon enough. Demands escalated. The diplomacy grew increasingly strained. By the reign of Emperor Maurice in the 580s, the reality of an equal relationship between Constantinople and the Khaganate had become difficult to maintain.
A historical illustration captures the intense and chaotic nature of the Avar raids into Balkan territories. Credit: Public Domain
Greece, as the frontline of Byzantine defense against the Avars
Byzantine Emperor Maurice (Maurikios) tried to push back, campaigning north of the Danube in operations that were militarily inconclusive and politically very risky. His soldiers, exhausted and unpaid, mutinied and killed him in 602, bringing the not-so-talented Phocas to power. The Danube frontier, already crumbling, effectively ceased to exist. What followed for the Balkans and Greece was not so much an invasion but a slow-but-steady immigration.
The Avars rarely settled new territories themselves. What they did instead was create the conditions through raiding, the collapse of Byzantine defensive infrastructure, and sheer disruption to force Slavic peoples from the northern parts of the Balkans to flood southwards. Over the late sixth and early seventh centuries, Slavic groups penetrated deep into Thrace, Macedonia, and eventually the Greek peninsula itself. Ancient cities emptied or shrank to shadows of their ancient selves. The road networks that had knitted late antique Greece together fell into disrepair and the sophisticated urban life of Roman Greece slowly but steadily collapsed.
Thessaloniki managed to survive this storm better than most of the other Greek-speaking cities of mainland Greece, though not without cost. The Avars, sometimes leading or directing Slavic forces, subjected the city to multiple sieges in the early seventh century (600s). Thessaloniki, the Byzantine Empire’s second-largest city, held out each time, and the Thessalonians interpreted their survival in explicitly miraculous terms. The devout Christian population believed that the city’s patron, Saint Demetrios, had intervened personally in its defense, a belief that generated one of the wealthiest hagiographic traditions of the entire Byzantine period.
Byzantine icon of Saint Demetrios, the patron saint of Thessaloniki, believed by the population to have miraculously defended the city during multiple Avar and Slavic sieges. Credit: Public Domain
The Avars against Constantinople itself
The 626 siege of Constantinople marked the Avar Khaganate at the peak of its ambition and, as it would prove, at the edge of its capabilities. The coordination with Persia was strategically a brilliant move. Two of Byzantium’s greatest enemies, the Avars from the north and the Persians from the East, were pressing simultaneously from opposite shores while the emperor was away.
Had the Slavic fleet successfully crossed the Golden Horn and landed Persian troops on the European side of Constantinople, the outcome might have been very different, and the entire southeastern part of Europe would have been completely different today.
However, it didn’t cross. Byzantine warships intercepted and wrecked the flotilla and without that, the siege lost its momentum. The land walls had never fallen to direct assault, anad we now know that they would not fall until 1453. The Avar army, lacking Persian reinforcement and having failed to breach the walls in nearly two weeks of effort, withdrew, utterly dissappointed. The Byzantines celebrated with everything they had. The Akathistos Hymn, one of the masterpieces of Orthodox Christian poetry, is closely associated with this event, its opening verses addressed to the Virgin Mary as defender of the city.
For the Khagan, the withdrawal was the beginning of the end for their expansionist dreams. The Avar Khaganate’s power began diminishing, as up to that point, part of their prestige was that the Avars were incontestable. That belief did not survive 626 intact.
The slow and painful end
Revolts broke out among subjugated peoples within years of the failed siege. The Bulgars carved out their own independent presence on the lower Danube, a development that would eventually produce one of Byzantium‘s most durable and treacherous neighbors. Internal succession crises pulled the Khaganate in different directions in very short periods of time. When Charlemagne turned his attention east in the 790s, he found an empire that had already done much of the work of destroying itself. His campaigns between 791 and 803 finished the job, smashing the Avar military capacity and seizing their accumulated treasure.
By the early ninth century (800s), the Avars had effectively ceased to exist as a political entity. They disappeared into the Slavic and Frankish populations around them, leaving behind those astonishing gold hoards in the hands of history and archaeology.
Illustration of Sclaveni between the Danube and the Balkan Mountains. Credit: Wikimedia Commons, Public Domain
What the Avars left behind
The Avars never ruled Greece. They never took Constantinople or even Thessaloniki, despite their desperate efforts to do so. By the conventional measures of imperial success, they failed at the things that mattered most—and yet the Greek world of the ninth century looked almost nothing like the Greek world of the fifth. The Avars bear huge responsibility for that slow and quiet transformation of what we now call northern Greece.
The Slavicization of the Balkans and the eventual settlement of large parts of the Greek peninsula was one of the most dramatic demographic shifts in European history. This happened mainly because of the Avar disruption in the Balkans. Byzantium spent generations afterwards attempting to reassert the Greek cultural and linguistic dominance across territories that had been thoroughly remade and effectively Slavicized. That effort played a huge role in shaping the distinct medieval Greek identity.
The Akathistos Hymn is still sung in Orthodox churches every year during Lent and is one of the most famous religious masterpieces the Orthodox Church has to offer. The walls of Constantinople, which held in 626 and held again and again afterwards, became the central fact of Byzantine strategic thinking for centuries. The Avar threat, in other words, produced some of Byzantium’s most well-known responses.
History tends to remember empires by what they conquer, but the Avar case suggests it might be worth paying more attention to what empires cause rather than gain.
