The Roman general Avidius Cassius, governor of Syria, who earlier had served under the late Emperor Lucius Verus, has by 175 virtually become a prefect of all of the eastern provinces, including control of the important province of Egypt.

In this year, Avidius Cassius takes the occasion of a rumor of Marcus Aurelius' death to proclaim himself emperor.

Marcus, very much alive, makes peace in the north with those tribes not already subjugated, and prepares to march against Avidius, who, having been accepted as Emperor by Syria, Palestine and Egypt, Cassius carries on his rebellion even after it has become obvious that Marcus is still alive.

Of the eastern provinces, only Cappadocia and Bithynia do not side with the rebels.

Cassius' fortunes decline quickly and the rebel general dies at the hands of one his own centurions after only one hundred days of power and before the campaign against him can begin.

The emperor, who apparently arrives in Antioch after the fact, uses the opportunity to make a tour of pacification and inspection in the East, first visiting Antioch, then crossing to Egypt.