Michael II, surnamed the Amorian or the Stammerer, reigned as Byzantine Emperor from December 820 to his death on 2 October 829, the first ruler of the Phrygian or Amorian dynasty.

Born in Amorium, Michael began his career as a soldier, rising to high ranks due to the favor of his old colleague, Leo V the Armenian (r. 813–820).

Nevertheless, Michael masterminds a conspiracy that overthrows and murders Leo on Christmas 820.

Immediately Michael faces the long revolt of Thomas the Slav, which almost costs him his throne and is not completely suppressed until spring 824.

The later years of Michael's reign are marked by two major military disasters with long-term effects, the beginning of the Muslim conquest of Sicily, and the fall of Crete to the Saracens.

Domestically, Michael supports and strengthens the resumption of official iconoclasm, which had begun again under Leo V.