Battle of Krasos The Battle of Krasos was a battle in the Arab – Byzantine Wars that took place in August 804 , between the Byzantines under Emperor Nikephoros I ( r . 802 – 811 ) and an Abbasid army under Ibrahim ibn Jibril . Nikephoros ' accession in 802 resulted in a resumption of warfare between Byzantium and the Abbasid Caliphate . In late summer 804 , the Abbasids had invaded Byzantine Asia Minor for one of their customary raids , and Nikephoros set out to meet them . He was surprised , however , at Krasos and heavily defeated , barely escaping with his own life . A truce and prisoner exchange were afterwards arranged . Despite his defeat , and a massive Abbasid invasion the next year , Nikephoros persevered until troubles in the eastern provinces of the Caliphate forced the Abbasids to conclude a peace . Background . The deposition of Empress Irene of Athens ( r . 797 – 802 ) , in October 802 , and subsequent accession of Nikephoros I signalled a more violent phase in the long history of the Arab – Byzantine Wars . Following a series of destructive annual raids across Asia Minor by the Caliphate , Irene seems to have secured a truce with Harun al - Rashid in 798 in exchange for the annual payment of tribute , repeating the terms agreed for a three - year truce following Harun ' s first large - scale campaign in 782 . Nikephoros , on the other hand , was more warlike and 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 . Nikephoros could not respond to this , as he faced an ultimately unsuccessful revolt of the Asian army under its commander - in - chief , Bardanes Tourkos . After disposing of Bardanes , Nikephoros assembled his army and marched out himself to meet a second , larger invasion under the Caliph himself . After Harun raided the frontier region , the two armies confronted each other 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 . Battle . In August 804 , Harun dispatched another raid under his general Ibrahim ibn Jibril . The Arabs crossed into Asia Minor through the Cilician Gates and raided freely . Nikephoros set out to meet them , but was forced to return before he could do so , due to some unspecified event at his back ( Warren Treadgold surmises news of a possible conspiracy ) . On his march home , however , the Arabs launched a surprise attack at Krasos in Phrygia and defeated his army . According to al - Tabari , the Byzantines lost 40 , 700 men and 4 , 000 pack animals , while the Emperor himself was wounded three times . The Byzantine chronicler Theophanes the Confessor confirms that the imperial army lost many men and that Nikephoros was almost killed himself ; saved only by the bravery of his officers . Aftermath . Preoccupied with trouble in Khorasan , Harun now accepted tribute and made peace . An exchange of prisoners was also arranged and took place during the winter at the two empires ' border , on the Lamos river in Cilicia ; some 3 , 700 Muslims were exchanged for the Byzantines taken captive in the previous years . During Harun ' s absence in Khorasan , however , Nikephoros used the opportunity to rebuild the destroyed walls of the towns of Safsaf , Thebasa , and Ancyra . The following summer he launched the first Byzantine raid for two decades ; into the Arab frontier district ( " thughur " ) in Cilicia . The Byzantine army raided and took prisoners as it went , even capturing the major Abbasid stronghold of Tarsus . At the same time , another Byzantine force raided the Upper Mesopotamia n " thughur " and unsuccessfully besieged the fortress of Melitene , while a Byzantine - instigated rebellion against the local Arab garrison began in Cyprus . Harun retaliated with a massive invasion in 806 , which forced Nikephoros to come to terms , but the Byzantine ruler soon violated them and prevailed over the Abbasid expeditions sent against him in 807 . Following renewed trouble in Khorasan , a peace treaty was signed in 808 which left the Byzantine frontier zone intact and ended the payment of tribute to the Caliphate .