Thomas, standing as champion to the poor…

Thomas, standing as champion to the poor and with the support of al-Ma'mun, marches west in spring 821 at the head of a motley force of Caucasian peoples whose sole bonds are to be found in their devotion to iconodule doctrine and their hatred of Michael's Iconoclasm.

In his account of the revolt, the historian Genesius lists a variety of peoples from whom the armies of the rebel were drawn: Saracens, Abasgians, Getae, Alans, Chaldoi, Armenians, Vandals and adherents of heretical sects of the Paulicians and Athinganoi.

Within a matter of months, only two themes in Asia Minor remain loyal to Michael, and in December 821, Michael besieges Constantinople.