Today in Middle Eastern history: the Battle of Lalakaon (863)
A Byzantine army defeats an Arab raiding party and, in the process, helps spark a period of imperial expansion.
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The two centuries-old Arab-Byzantine conflict was on the cusp of a total shift in fortunes in the middle of the 9th century. Where the Arabs had been the aggressors for most of the period following the Battle of Yarmouk in 636, the Abbasid Caliphate now found itself falling apart, with local principalities asserting more and more autonomy from Baghdad and the caliphate’s own Turkish soldiery causing discord at the imperial center. Over the succeeding two centuries, give or take, the Byzantines would take advantage of the breakdown within the caliphate to begin pushing back. But that was all in the future. In 863 the Byzantines were still struggling to fend off multiple threats from several directions—the Arab emirates of Melitene (modern Malatya), Tarsus, and Qaliqala (modern Erzurum) and the Paulicians in Tephrike (modern Divriği) in the east, and the Bulgarians in the west. Then in one fell swoop, at the Battle of Lalakaon that September, everything started to change.

Although it foreshadowed a period when the empire would mostly take the offensive against its enemies, the Byzantine victory at Lalakaon was a defensive one. Emir of Melitene—and thorn in Constantinople’s side—Umar al-Aqta invaded the eastern empire on a raiding mission. He and the emir of Tarsus, Ali ibn Yahya, had carried out a devastating joint raid in 860, with Ali invading the empire as the Byzantines were recovering from an assault by Umar and the Paulicians. With the weakening of central Abbasid authority, these local emirates had assumed responsibility for carrying out annual attacks on the Byzantines that the caliphs had once led personally. Melitene and Tarsus arranged a similar joint campaign in 863, though around this time Ali ibn Yahya was appointed governor of Armenia, so Umar worked instead with an Abbasid general named Jaʿfar ibn Dinar al-Khayyat. It’s unclear whether Jaʿfar was the new governor of Tarsus or just the caliphal official charged with organizing that year’s raids, but that doesn’t really matter for our purposes.
Before we go any further we should probably say something about the Paulicians, who played an important role on the Byzantine-Arab frontier during the 8th and 9th centuries and are about to disappear from history. They’re a fairly obscure group—it’s not clear, for example, why they were called the “Paulicians,” though it seems the name derived either from the Apostle Paul or a third century bishop of Antioch named Paul of Samosata, who was one of the group’s early leaders. They show up in the 7th century under the leadership of an Armenian man named Constantine, who also goes by Silvanus. As far as the Byzantines were concerned they were heretics, adhering to a dualist belief system (i.e., material world bad, spiritual world good) that may also have been adoptionist (teaching that Jesus was not begotten by God but was rather chosen later in life to carry out his divine mission) and non-trinitarian. It may have been an offshoot of Marcionism, an earlier dualist movement that really favored Paul. It’s hard to know any of this for certain because most of the information about the Paulicians comes from polemics against them.
Although they were labeled heretics, the Paulicians managed to form an alliance of sorts with iconoclasts during the Byzantine Empire’s 8th-9th century iconoclasm period, so they actually thrived for a while, especially given that they could be a reliable source of military manpower for an empire in desperate need of it. But when the iconoclasts lost their struggle against imperial iconophiles, the Paulicians suffered badly. Tens of thousands are believed to have been killed in purges in the early 840s, at which point their leader, a man called Karbeas, led many of the group east, founded a couple of new cities (including Tephrike), and aligned himself and his soldiers with the Arabs of Melitene. There were probably Paulicians with Umar on his raid, though there’s no specific information to that effect. It’s possible that Karbeas was among them, though as we’ll see that claim is based mostly on a coincidence.
Initially, the Arab raid of 863 went as those raids usually did, which is to say successfully. But then Umar, apparently feeling extra confident, asked Jaʿfar for permission to continue deeper into Byzantine territory. Jaʿfar approved, but took his own forces back to Tarsus to count the booty. Umar, again probably with some Paulicians, continued north all the way to the shores of the Black Sea. The Byzantine Emperor, Michael III, ordered his uncle and Domestic of the Schools (top general, basically) Petronas to put together an army and deal with the Arab invaders. Whether Michael personally led this army is unclear—a fairly contemporary Arab source, al-Tabari, says he did, while later (and possibly biased) Byzantine sources do not mention his presence. The size of the opposing forces is also unclear, as the Arabs probably exaggerated the size of the Byzantine army and the Byzantines almost certainly exaggerated the size of Umar’s raiding party. Suffice to say the Byzantines most likely outnumbered the Arabs by a substantial margin.

The Byzantines were able to surround Umar near the Lalakaon River, whose modern correspondent is unknown though it’s believed to be Turkey’s Kızılırmak River, also known as the Halys. The Arabs attempted to break out of their envelopment but failed, leaving most of them (including Umar) dead on the battlefield. If Karbeas was with Umar on this raid then he was probably killed here as well. Again, there’s no proof that he was at Lalakaon, let alone that he died there, but he did kick the bucket in the year 863 so there’s your coincidence. The Paulicians continued to raid cities in the Byzantine Empire for several more years, but an imperial army defeated them either in 872 or 878 in a battle that seems to have broken the back of the movement for good.
The Byzantines decided to follow up their victory by invading Arab-controlled Armenia, where sometime that fall their forces killed Ali ibn Yahya in battle. Suddenly the two biggest Arab nuisances to the empire were dead and the Emirate of Melitene’s capacity to threaten the empire was largely destroyed. The Abbasid Caliphate, sinking deeper into internal crisis, could do nothing about it. The Byzantines, meanwhile, were just a couple of decades removed from the devastating Arab sack of the city of Amorium in 838 and badly needed the morale boost that Lalakaon and its aftermath provided. Forestalling future Arab raids in the east also provided a tangible benefit, in that the Byzantines were able to shift their military focus west and invade Bulgaria the following year.
The Bulgarians were Christianizing, and a show of Byzantine force was just the thing to keep them from going over to the Pope and encourage them to adopt Byzantine Christianity instead. Technically it was all the same Christianity at this point, but while the full East-West Schism was still a couple of centuries away the rift between Rome and Constantinople was already quite significant. The Bulgarians placed themselves under Byzantine religious and cultural influence, which greatly diminished the threat they posed to the empire on its western frontier. This, in turn, allowed the Byzantines to refocus their military attention east and was a key factor in the period of imperial military success that followed.