Johannes - Augustus (usurper) of Imperium Romanum from 423 AD to 425 AD
Iohannes Augustus was a Roman usurper (423–425) against Valentinian III.

He was a senior civil servant at the time of his elevation, and Procopius praised him as "both gentle and well-endowed with sagacity and thoroughly capable of valorous deeds." Unlike the Theodosian emperors, he tolerated all Christian sects.

Joannes had hoped that he could come to an agreement with the Eastern Emperor, but when Theodosius II elevated Valentinian III to co-emperor, he knew he could only expect war.

When Ravenna was besieged, Johannes was betrayed by the garrison, captured, tortured, humiliated, and finally decapitated.
Emperor (usurper) Johannes of the Roman Empire