The Levant Egypt North Africa Anatolia & Constantinople Border conflicts Sicily and Southern Italy Naval warfare Byzantine reconquest The Battle of Lalakaon (Greek: Μάχη τοῦ Λαλακάοντος), or Battle of Poson or Porson (Μάχη τοῦ Πό(ρ)σωνος),[1] was fought in 863 between the Byzantine Empire and an invading Arab army in Paphlagonia (modern northern Turkey).

These expeditions were launched almost annually from bases in the Arab frontier zone, and acquired a quasi-ritualistic character as part of the Muslim jihad (holy war).

[2] The Byzantines were generally on the defensive during the 7th–9th centuries,[3] and suffered some catastrophic defeats, such as the razing of Amorium (home city of the reigning Amorian dynasty) in 838.

Nevertheless, the Arabs escaped the Byzantines and continued their raid north into the Armeniac Theme, reaching the Black Sea and sacking the port city of Amisos.

Byzantine historians report that Umar, enraged that the sea blocked his advance, ordered it to be lashed, but modern scholars consider this account was most likely inspired by a similar story about Xerxes during the Greco-Persian Wars.

[15][16][17] When Michael learned of the fall of Amisos, he assembled a huge force—al-Tabari claims 50,000 men—under his uncle Petronas, who held the post of Domestic of the Schools (commander-in-chief of the Byzantine field army) and Nasar, the strategos (military governor) of the Bucellarian Theme.

The Byzantines hailed them as revenge for the sack of Amorium 25 years earlier, the victorious generals were granted a triumphal entry into Constantinople, and special celebrations and services were held.

[28][30] Al-Tabari reports that the news of the deaths of Umar and Ali al-Armani—"strong defenders of Islam, men of great courage who elicited enormous praise among the frontier districts where they served"—provoked an outpouring of grief in Baghdad and other cities, culminating in riots and looting.

Although private donations and volunteers for the holy war began to gather at the border, "the central authorities [were not] prepared to send a military force against the Byzantines on their own account in those days" because of ongoing internal turmoil in the Abbasid Caliphate.

[31] The removal of the eastern threat and increasing Byzantine confidence also opened up opportunities in the west, where the Bulgarian ruler Boris (r. 852–889) had been negotiating with the Pope and Louis the German (r. 817–876) for the conversion of himself and his people to Christianity.

The victorious eastern armies were transferred to Europe and invaded Bulgaria in 864, a demonstration of military might which convinced its ruler to accept Byzantine missionaries instead.

[1][30][32] According to the French Byzantinist Henri Grégoire, the Byzantine successes against the Arabs, which culminated in the Battle of Lalakaon, inspired one of the oldest surviving acritic (heroic) poems: the Song of Armouris.

[33] A battle in the Byzantine epic cycle around Digenis Akritas is also reminiscent of the events at Lalakaon, as the eponymous hero surrounds an Arab army near Malakopeia.