Michael I (Greek: Μιχαῆλ A) was Roman Emperor and Caliph of Islam from 859 to 864, the last of the Isaurian Dynasty. He succeeded his grandfather, Heraclius II, during a period of chaos and uncertainty that the empire was unprepared to deal with after the respite of the beginning of the century, and Michael soon found himself fighting for survival. In 860 he formed an alliance with Theodemar, the powerful king of Africa, giving himself the ability to call upon African assistance should the empire ever be in mortal danger.

In 864 the Bulgarian Empire launched its greatest campaign yet, smashing through the Cilician frontier fortifications and forcing its way into the wealthy province of Syria. Michael immediately sent word to Theodemar, asking for help, but he was fully aware that the African army couldn't arrive in time to save him. By August the Bulgars were marching on Antioch, and while the Senate and many other wealthy citizens fled to safety in Egypt, Michael resolved to remain in the city to command the defenses.

Antioch fell on the 29th September and Michael was killed in the ensuing sack, just weeks before the African army finally arrived in the region. Theodemar's Africans, along with the remnants of the Roman army, were able to liberate Antioch and drive the Bulgars out of Syria before the end of the following year, and Theodemar was subsequently acclaimed the Emperor Basil I. By 867 he had recovered much of Anatolia as well, undoing the losses of the past hundred years. Never again would Romania's very existence be in such deadly peril.

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