Abbasid invasion of Asia Minor (806)

Map of Byzantine Asia Minor and the Byzantine–Arab frontier region ca. 780

Date	Summer 806
Location	Central and eastern Asia Minor
Result	Abbasid victory; temporary resumption of tribute by the Byzantines

Belligerents

Abbasid Caliphate

Byzantine Empire

Commanders and leaders

Harun al-Rashid

Nikephoros I

Strength

over 135,000 (al-Tabari)

unknown

The Abbasid invasion of Asia Minor in 806 was the largest operation ever launched by the Abbasid Caliphate against the Byzantine Empire. The expedition was commanded in person by the Abbasid Caliph Harun al-Rashid (reigned 786–809), who wished to retaliate for the Byzantine successes in the Caliphate's frontier region in the previous year and impress Abbasid might upon the Byzantine emperor, Nikephoros I (r. 802–811). The huge Abbasid army, according to Arab sources numbering more than 135,000 men, raided across Cappadocia unopposed, capturing several towns and fortresses, most notably Herakleia, and forcing Nikephoros to seek peace in exchange for tribute. Following Harun's departure, however, Nikephoros violated the terms of the treaty and reoccupied the frontier forts he had been forced to abandon. Harun's preoccupation with a rebellion in Khurasan, and his death three years later, prohibited a reprisal on a similar scale. Moreover, the Abbasid civil war that began after 809 and the Byzantine preoccupation with the Bulgars contributed to a cessation of large-scale Arab–Byzantine conflict for two decades.

Following the deposition of Byzantine empress Irene of Athens in October 802 and the accession of Nikephoros I in her place, a more violent phase in the long history of the Arab–Byzantine Wars began. Following a series of destructive annual raids across Asia Minor by the Abbasid Caliphate, Irene seems to have secured a truce with the Caliph Harun al-Rashid in 798 in exchange for the annual payment of tribute, repeating the terms agreed for a three-year truce after Harun's first large-scale campaign in 782. Nikephoros, on the other hand, was more warlike—a Syriac source records that when he learned of Nikephoros's accession, a Byzantine renegade warned the Arab governor of Upper Mesopotamia to "throw away his silk and put on his armour". In addition, he was determined to refill the imperial treasury by, among other measures, ceasing the tribute. Harun retaliated at once, launching a raid under his son al-Qasim in spring 803. Nikephoros could not respond to this, as he faced a large-scale revolt of the Byzantine army of Asia Minor under its commander-in-chief, Bardanes Tourkos. After disposing of Bardanes, Nikephoros assembled his army and marched out to meet a second, larger invasion under the Caliph himself. After Harun raided the frontier region, the two armies confronted one another for two months in central Asia Minor, but it did not come to a battle; Nikephoros and Harun exchanged letters, until the Emperor arranged for a withdrawal and a truce for the remainder of the year in exchange for a one-off payment of tribute.

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