Maurice's Balkan campaigns

Maurice's Balkan campaigns were a series of military expeditions conducted by the East Roman (Byzantine) emperor Maurice (reigned 582–602) in an attempt to defend the Balkan provinces of the East Roman Empire from Avars and Slavs. Maurice was the only East Roman emperor, except for Anastasius I, who did his best to implement determined Balkan policies during Late Antiquity, paying adequate attention to the safety of the northern frontier against barbarian incursions. During the second half of his reign, the Balkan campaigns were the main focus of Maurice's foreign policies, as a favourable peace treaty with Persia in 591 enabled him to shift his experienced troops from the Persian front to the region. The refocusing of Roman efforts soon paid off: the frequent Roman failures before 591 were succeeded by a string of successes afterwards.

Although it is widely believed that his campaigns were only a token measure and that Roman rule over the Balkans collapsed immediately after his overthrow in 602, Maurice was in fact well on his way to forestalling the Slavic landfall on the Balkans, nearly preserving the order of Late Antiquity there. His success was only undone over ten years after his overthrow. Retrospectively, these campaigns were the last in the series of classical Roman campaigns against the Barbarians on the Rhine and Danube, effectively delaying Slavic landfall on the Balkans by two decades. With respect to the Slavs, these campaigns had the typical trait of Roman campaigns against unorganized tribes and of what we now call asymmetric warfare.

Balkan peninsula before 582
At Maurice's accession, the greatest omissions of his predecessors were to be found in the Balkans. Justinian I neglected Balkan defences against the Slavs, who threatened the frontier since 500 and pillaged the Balkan provinces ever since. Although he rebuilt the fortifications of the Danube Limes, he forwent campaigns against the Slavs in favour of a policy focusing on western and oriental theatres. His nephew and successor Justin II played off the Avars against the Gepids and later on against the Slavs. But this only allowed the Avar Khaganate to become a more powerful threat than Gepids and Slavs. As Justin II let the Avars attack the Slavs from Roman territory, they soon noted where the most booty was to be made. To make matters worse, Justin II started the Roman-Persian War of 572–591, which tied down forces in the east at a time when they were needed in the Balkans. Maurice's predecessor and father-in-law Tiberius II Constantine emptied the treasury. For all those reasons, the Slavic incursions in the Balkans continued.

A few months before Maurice's accession in the winter of 581/2 the Avar Khagan Bayan, aided by Slavic auxiliary troops, took Sirmium, a large fortified settlement south of the Danube. Doing this, Bayan established a new base of operations within Roman territory from which he could raid the anywhere in the Balkans unhindered. The Avars were only compelled to leave territory once the Romans agreed to pay 80,000 solidi annually. The Slavs, partially under Avar rule, were not bound by the treaty and continued to pillage south of the Danube, making the Avars and Slavs quite different threats.

Avar and Slavic incursions, 582 to 591
In 583 the Avars demanded an increase in tribute to 100,000 solidi. Maurice decided to end all tribute to the Avars, concluding that additional concessions would only provoke additional demands. The renewed Avar invasion began in 583 with the capture of Singidunum after stiff resistance. The Avars quickly moved east and captured Viminacium and Augustae, and began attacking as far southeast as Anchialus after only three months into the war. A Roman embassy met the Avars near Anchialus, but negotiations broke down after the Avar Chagan threatened further conquests, provoking an irate response out of Comentiolus, one of the Roman ambassadors. Nevertheless, Maurice established peace in 584 when he agreed to pay the Avars initial demands of 100,000 solidi. However, the Slavs were unhindered by the treaty, and began to raid further south into Macedonia and Greece, evidenced by many coin hoards in the region, particularly in Attica near Athens and in the Peloponnese.

As Maurice's forces were tied down in a war against the Persians caused by Justin II, (see Roman-Persian Wars for details), he could muster only a small army against the Avars and Slavs marauding Balkans. His efforts were hampered by the fact that operations on the Balkans were a completely defensive matter. As opposed to the Persian war theatre, the Balkan theatre proved little possibility for a soldier to bolster his pay by pillaging, thus making fighting rather unattractive. Maurice's badly motivated troops found it difficult to achieve even minor and local success. Rather an exception, a victory won by Comentiolus at Adrianople 584/585 deflected Slavic incursions to Greece. The evident destruction of vast parts of old Athens probably happened in this period.

The situation in Balkans deteriorated in such a manner that in 585 the Persian Shah Hormizd IV could reasonably hope to negotiate a peace treaty leaving Armenia to the Persians. Maurice rejected the offer, being able to negotiate much more favourable peace terms in 591, after substantial successes on the battlefield. For the time being, however, he had to abide by Avar and Slavic incursions and hope that his forces garrisoned at Singidunum could deter the invaders, posing a constant threat to the Avar homeland, just on the other side of the Danube. Roman presence at Singidunum was strong enough to effect constant break-offs of Avar raids. However, it could not prevent the attacks. Despite the Roman garrison at Singidunum, the Avars destroyed the fortified towns of Ratiaria and Oescus on the Danube and besieged Thessaloniki in 586, accompanied by Slavic raids down to the Peloponnese. Under the leadership of Comentiolus, the outnumbered Roman Army avoided any direct confrontation and restricted itself to disturbing the Avar raids by skirmishes and night attacks - a tactical expedient advised in Maurice's Strategikon. In 586 and 587, Comentiolus won several victories against the Slavs on the lower Danube and nearly caught the Avar Khagan Bayan two times. At Tomis, on the shores of the Black Sea the Khagan escaped via the lagoon-shaped coast, whereas an ambush on the south slope of the Balkan mountains was thwarted by miscommunication amongst Roman troops:
 * "a beast of burden had shucked off his load. It happened as his master was marching in front of him. But the ones who were coming from behind and saw the animal dragging his burden after him, had shouted to the master to turn around and straighten the burden. Well, this event was the reason for a great agitation in the army, and started a flight to the rear, because the shout was known to the crowd: the same words were also a signal, and it seemed to mean “run”, as if the enemies had appeared nearby more rapidly than could be imagined. There was a great turmoil in the host, and a lot of noise; all were shouting loudly and goading each other to turn back, calling with great unrest in the language of the country “torna, torna, fratre”, as a battle had suddenly started in the middle of the night."

The quoted phrase at the root of the misunderstanding is held to be the first sample of the Romanian language.

The following year, Priscus took over from Comentiolus. His first campaign in Thrace and Moesia turned out to be a fiasco, even encouraging the Avars to advance as far as the Marmara Sea. As the state of the Avar bridges across the Sava river near Sirmium deteriorated, Avar pressure decreased nevertheless.

Even so Maurice did all he can to enforce his troops on Balkans, as Slavic pillaging continued. He hoped to acquire the money by cutting soldier's payment by a quarter. Announcing these plans led to a mutiny on the Persian front in 588, which in turn forced Maurice to abandon the idea. As a consequence, in the Balkans Maurice had only limited means to keep Avars and Slavs at bay for the next three years.

Campaigns in 591–595
In the late summer of 591 Maurice finally made peace with the Persian Shah Khosrau II, the latter ceding Armenia to the Roman empire. Finally, the veterans of the Persian wars were at his disposal, and so was the recruiting potential of Armenia. Decreasing Avar and Persian pressure enabled the Romans to focus on the Slavs in 590/591. Maurice had already visited Anchialos and other cities in Thrace personally in 590, to oversee reconstruction and to boost the morale of his troops and the local population. After making peace with Persia, he speeded up this development by redeploying troops to Balkans.

In 592 his troops retrieved Singidunum, which was to be however lost to the Avars again. Smaller Roman units were involved in policing actions against Slavic raiders in Moesia, reestablishing lines of communication between the Roman cities. Maurice aimed to reestablish a sturdy defense line along the Danube river, as Anastasius I had done a century before. Furthermore, he intended to keep Avars and Slavs off Balkan territory by counter-invading their homelands, so as to enable Roman troops to increase their pay by pillaging in hostile territory, making these campaigns more attractive.

Maurice's general Priscus began to hinder the Slavs crossing the Danube in spring 593. He routed them several times before crossing the Danube to carry on the fight in the uncharted swamps and forests of modern-day Greater Wallachia until autumn. Then, he disobeyed Maurice's order to spend the winter on the northern Danube bank, among frozen swamps and rivers and leafless forests. Instead, Priscus retired to winter quarters in Odessos (modern Varna). This led to a new Slav incursion 593/594 in Moesia and Macedonia, during which the towns of Aquis, Scupi and Zaldapa in Dobruja were destroyed.

In 594 Maurice disposed of Priscus and replaced him by his own, rather inexperienced brother Peter. Despite initial failure, Peter maintained his position, defeated the Slavs (Priscus speaks about Bulgars) at Marcianopolis and patrolled the Danube between Novae (modern Svishtov) and the Black Sea. In late August, he crossed the Danube near Securisca west of Novae and fought his way to the Helibacia river, effectively disturbing Slav preparations for new pillaging campaigns.

This success enabled Priscus, who had in the meantime been entrusted with the command of another army upstream, to prevent an Avar siege of Singidunum in 595 in a combined action with the Roman Danube fleet. The fact that the Avars retreated and gave up their plans to destroy the city and deport its inhabitants, as opposed to their conquest of 584, showed their lack of confidence and the threat they saw in this border fortress.

Subsequently, the Avars turned off to Dalmatia, where they sacked several fortresses, avoiding direct confrontation with Priscus. Roman commanders were never unduly concerned about barbarian incursions into this remote and impoverished province, so Priscus had to act cautiously. He could not afford to neglect the defence of the Danube, so he dispatched a small force to check the Avar advance. This small force hampered Avar advance and even retrieved part of the booty.

A quiet interlude, 596–597
After this only moderately successful Avar raid into Dalmatia, there was only minor action in Balkans for about one and a half years. Discouraged by the lack of success, the Avars saw more prospect for booty in the West and therefore raided the Franks in 596. Meanwhile, the Romans used Marcianopolis near Odessos as a base of operations on the lower Danube against the Slavs, rather than exploiting Avar absence. No notable Slav raids took place in this time, either.

Renewed campaigns, 597–602
Strengthened by Frankish pay-offs, the Avars resumed their Danubian campaigns in autumn 597, surprising the Romans. They even managed to besiege Priscus' army in Tomis. On 30 March 598 however they lifted the siege, since Comentiolus had led an army of rather inexperienced soldiers over the Haemimons and was moving along the Danube up to Zikidiba, near modern-day Medgidia, just 30 km from Tomis. For reasons unknown, Priscus did not pursue the Avars and aid Comentiolus. The latter was forced to evade to Iatrus, where his troops were nonetheless routed and had to fight their way south over the Haemus range. The Avars utilized this victory and advanced to Drizipera near Arkadiopolis, between Adrianople and Constantinople, where a large part of their army and seven sons of the Avar Khagan were killed by the plague. Comentiolus was temporarily relieved of his command and replaced by Philippicus, whereas Maurice summoned the Circus factions and his own bodyguards to defend the long walls east of Constantinople. For the time being, Maurice managed to buy off the Avars, and in the same year, a peace treaty was concluded with Bayan, the Avar Khagan, explicitly allowing Roman expeditions in Wallachia. The Romans used the remainder of the year to reorganize their forces and analyze the causes of failure.

Then the Romans violated the treaty: Priscus advanced in the area surrounding Singidunum and wintered there in 598/599. In 599 the armies of Priscus and Comentiolus moved downstream to nearby Viminacium and crossed the Danube. On the north bank, they defeated the Avars in open battle in their own homeland. This was not only the first Avar defeat in their own homeland, but also saw the death of several more sons of Bayan Khagan. Priscus subsequently thrust north into the Pannonian plain, the Avar homeland. He defeated the Avars deep within their empire, whereas Comentiolus remained near the Danube. Afterwards Priscus devastated vast tracts of the land east of the Tisza, much in the same way Avars and Slavs had done in the Balkans before. Several Avar tribes and their Gepid subjects suffered particularly high casualties. Two other battles on the banks of the Tisza meant further Avar defeats.

Furthermore, the Exarch of Ravenna Callinicus repulsed Slav attacks on Istria in 599.

In autumn 599 Comentiolus reopened the Gate of Trajan pass, near modern-day Ihtiman. This mountain pass had not been used by the Romans for decades. In 601 Peter advanced to the Tisza and kept the Avars away from the Danube cataracts, the latter being vital for the Roman Danube fleet in order to maintain access to the cities of Sirmium and Singidunum. In 602 Peter inflicted another severe defeat on the Slavs in Wallachia, whereas the Avar Khaganate was opposed by the Antes and was on the brink of collapse due to the mutiny of several Avar tribes. One of these rebellious tribes even defected to the Roman side. For the time, the Romans had successfully reestablished the Danube line, and forward defense in the hostile territories of Wallachia and Pannonia was waged with success. But when Maurice ordered the army to spend the winter of 602/603 on the northern bank of the Danube, as to further his success and to save money on quarters, his troops mutinied as they had done in 593. While Priscus back then had used his own judgment and initiative, Peter did not dare disobey the emperor's orders. He therefore soon lost control of his army, which marched straight to Constantinople. This led to the well-known overthrow and death of Maurice, the first successful coup d'état in Constantinople.

Balkan peninsula after 602
Maurice had pacified the Balkan borders, a feat not performed since the reign of Anastasius I. Avars and Slavs had been kept sternly at bay. The provinces were at a stage of potential recovery; reconstruction and resettlement were the keys to firmly secure Roman rule again. Maurice had planned to settle Armenian militia peasants within the depopulated areas and to romanize the Slavs settlers in the area. After his overthrow, these plans went astray as well as the campaigns and the possible destruction or submission of the Avar empire. The new Roman emperor Phocas (602–610) would have to fight against the Persians once more: the eastern enemy occupied Armenia in the first phase of the new war. Therefore, Phocas could not continue the campaigns on the same scale as before, or settle any Armenians in Balkans. This finally led to the decline of Roman rule in the Balkan Prefecture, marking the end of Late Antiquity in that region.

Phocas' Balkan campaigns? - Silence before the storm, 602–612/615
The widespread opinion that Roman control of Balkans collapsed immediately after his accession, is against all evidence.

Phocas indeed continued Maurice's campaigns on an unknown scale (albeit with likely much less rigour and discipline) and probably transferred forces to the Persian front after 605. But even after 605, it is unlikely that he withdrew all forces from the Balkans, given his Thracian heritage. There is no archaeological evidence such as coin hoards or destruction showing Slav or Avar incursions, let alone a total collapse of Roman power during Phocas' reign. On the contrary, it is known that refugees from Dardania, Dacia, and Pannonia sought protection in Thessalonica only under his successor Heraclius (610–641). Even a moderate recovery under Phocas may have taken place. Evidently, many fortresses were rebuilt either under Maurice or Phocas. But even so, it was Phocas' inaction, more or less imposed by the deteriorating situation on the Persian front, that paved the way for the massive invasions of Heraclius' first decade and for the eventual collapse of Roman rule over the Balkans.

The great Slav and Avar raids, 612–626
Very likely Heraclius withdrew all Roman forces from the Balkans. The civil war against Phocas led to a deterioration of the Persian front unequalled by anything before. This, alongside successful campaigns against the Lombards in Friuli in 610 and against the Franks in 611, probably encouraged the Avars and their Slav subjects to renew their incursions some time after 612. At the latest, the Persian capture of Jerusalem in 614 was the key event showing the unlikeliness of Roman retaliation. In fact, the 610s chronicles again record wholesale pillaging. Cities like Justiniana Prima and Salona succumbed to these attacks. It is unknown at which time a certain area was suberged by Slavic tribes but some events clearly stick out; the destruction of Novae after 613, the conquest of Naissus and Serdica as well as the destruction of Justiniana Prima in 615, three sieges of Thessalonica (604?, 615 and 617), the battle of Heraclea Perinthus on the shores of the Marmara sea in 619, Slavic raids on Crete in 623 and the siege of Constantinople in 626. From 620 on, archaeological evidence too proves Slav settlements within the destructed Balkan regions.

Slow decline of the Balkans after 626
Some cities survived the Avar and Slav incursions and were able to maintain communications with Constantinople via sea and rivers. Chronicles mention a Roman commander of Singidunum in the middle of Heraclius' reign. But also on many Danube tributaries accessible by ship, Roman settlements survived, as for instance modern-day Veliko Tarnovo on the Yantra River, which even has a church built in the 7th century. Heraclius made use of the short time between the end of the last war against Persia in 628 and the commencement of Arab attacks in 634 to try to re-establish at least some sort of authority over the Balkans. Clear evidence is the construction of the fortress of Nicopolis in 629. Heraclius also allowed the Serbs to settle in the Balkans as foederati against the Avars, and the Croats in Dalmatia and Lower Pannonia; the Croats even pushed the frontier to the Sava in 630. Having to fight off the Arabs in the east, however, he could not finish his project. Roman rule in rural areas of the Balkans was limited to the successes attained in short summer campaigns. The cities of the Balkans, traditionally the major centres of Roman civilization, had degenerated from the populous, wealthy and self-sufficient polis of Antiquity to a limited, fortified kastron. They were unable to form a cultural and economic nucleus upon which the Roman state could build. Their population was consequently assimilated by the Slavic settlers. Even so, some cities along the Danube retained their Roman traits until the Proto-Bulgarian invasion of 679, also being under Byzantine rule until this date. The fact that the Proto-Bulgarians used a debased form of Greek as administrative language shows that Roman population and administrative structures existed there even after 679. In Dalmatia, Romance idioms (Dalmatian) persisted into the late 19th century, whereas in Macedonia, the ancestors of modern-day Aromanians survived as transhumant nomads. In dispute to this very day is the origin of the Romanians. According to Robert Roesler, the ancestors of modern-day Romanians formerly lived south of the Danube and migrated to Romania: a thesis dear to Hungarians in their nationalistic feuds with Romania over Transylvania. The other theory, supported by Romanian nationalists, is that a Daco-Romanian continuity originated from the Roman conquest of Dacia in 106. In central Albania, a small ethnic group, unnoticed over centuries of Roman rule, retained its pre-Roman language and also survived Slavic landfall, the ancestors of modern-day Albanians. Summed up, the decline of Roman power on the Balkans was a slow affair, only taking place due to the lack of military Byzantine presence. Being short on troops in the Balkans, there was no possibility for Byzantium to provide for safe communication between the cities. Byzantium could only locally impose a rule over the Balkan Slavs and only on a short-term basis, not enough to assimilate them. Byzantium, however, used any opportunity given by pauses of activity on the Arab front to subjugate the Slavs and resettle them en masse to Asia Minor. With a delay of two centuries, Thrace and Greece were re-hellenized, whereas the remainder of the Byzantine Balkans was conquered by the Bulgarians except for Albanians and Vlachs/proto-Romanians, permanently Slavicized.

Retrospective
In the end, the successes of Maurice's campaigns were foregone by Phocas. Maurice's hopes for rebuilding Balkans and resettling Armenian militia peasants to the depopulated areas were not realized. Heraclius would do even less for the Balkans. Therefore, the only immediate consequence was the mentioned delay in Slavic landfall on the Balkans. For this reason, it is often falsely and superficially assumed that Maurice's Balkan campaigns were a failure.

Probably, Avar defeats in the late part of the campaigns from 599 on had a long term impact. The Avars had been bloodily defeated in their own country and had proven to be unable to protect themselves, let alone their subjects. Until the battle of Viminacium in 599, they were held to be invincible, allowing them to thoroughly exploit their subjects. After this had been proven wrong, the first rebellions occurred, to be crushed after 603. The Avars were able to score further successes against the Lombards, Franks and Romans; however, they were unable to restore their old reputation. This can explain the Slavic uprising under the leadership of Samo in 623, three years before the abortive Siege of Constantinople.

Maurice's campaigns put an end to Avar dreams of hegemony on the Balkans and paved the way for an end of the Avar threat. The Khagan's power collapsed only after the abortive siege of Constantinople in 626 and; the Avar Khaganate would be eventually destroyed much later by Charlemagne in (791–803). The Avar Khaganate empire ceases to exist after 790 AD. The Muslim conquests, beginning in the 630s, led to the loss of all the Oriental provinces of the Roman Empire. The constant Arab threat over strategically important Asia Minor had a great impact on Balkans. Several decades were to pass before Constantinople could regain the initiative and reconquer parts of Slav-controlled areas (Sklavinia). Several centuries were to pass before Basil II was to bring, by fire and sword, the entire the Balkans under Byzantine control again.