The Abbasids had launched Process_start a huge expedition Attack with two separate armies in retaliation for the Byzantine emperor Theophilos 's successes the previous year , and aimed Aiming to sack Destroying Amorion , one of Byzantium 's largest cities .

Theophilos with his army confronted Confronting_problem the smaller Muslim army , under the Iranian vassal prince Afshin , at Dazimon .

The numerically superior Byzantine army was initially successful , but when Theophilos resolved Resolve_problem to lead an attack Attack in person , his absence from his usual post caused Causation panic among the Byzantine troops , who feared that he had been killed Killing .

Theophilos and his guard were besieged Besieging for a while on a hill , before making good their escape Escaping .

The Abbasid campaign was led Causation personally by the Caliph al-Mu'tasim ( reigned 833–842 ) , in retaliation Revenge to a virtually unopposed expedition launched Motion by the Byzantine emperor Theophilos ( r. 829–842 ) into the Caliphate 's borderlands the previous year .

The northeastern army defeated Conquering the Byzantine forces under Theophilos at Anzen , allowing Preventing_or_letting the Abbasids to penetrate deep into Byzantine-held Asia Minor and converge upon Ancyra , which they found Know abandoned GiveUp .

Faced with intrigues at Constantinople and the rebellion of the large Khurramite contingent of his army , Theophilos was unable to aid Assistance the city .

The conquest Attack of Amorium was not only a major military disaster Catastrophe and a heavy personal blow for Theophilos , but also a traumatic event Social_event for the Byzantines , its impact resonating in later literature .

The sack did not ultimately alter Change the balance of power , which was slowly shifting Change in Byzantium 's favour , but it thoroughly discredited Judgment_communication the theological doctrine of Iconoclasm , ardently supported Supporting by Theophilos .

As Iconoclasm relied Supply heavily on military success for its legitimization , the fall of Amorium contributed Giving decisively to its abandonment shortly after Theophilos 's death in 842 .