The Battle of Anzen or Dazimon is fought on 22 July 838 at Anzen or Dazimon (now Dazman, Turkey) between the Byzantine Empire and the forces of the Abbasid Caliphate.

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

Theophilos with his army confronts the smaller army, under General Afshin, at Dazimon.

The numerically superior Byzantine army is initially successful, but when Theophilos resolves to lead an attack in person, his absence from his usual post causes panic among the Byzantine troops, who fear that he has been killed.

Coupled with a fierce counterattack by Afshin's Turkish horse-archers, the Byzantine army breaks and flees.

Theophilos and his guard are besieged for a while in a hill, before making good their escape.

The defeat opens the way for the brutal sack of Amorion a few weeks later, one of the most serious blows Byzantium suffers in the centuries-long Arab–Byzantine Wars.