The Classical Calendar: March 16
Valentinian III is assassinated
So Valentinian was assassinated by two Hunnish followers of a rival.
At this point the Roman Empire was struggling to repel the invading Huns. Those opposed to the emperor used this as a tool in order to oust him. in particular one Petronius Maximus, who was probably the one who put the Hunnish assassins up to their task.
He did, however, get his comeuppance, when, having bought the position of emperor, and suddenly realising that he didn’t have the required skills to restabilise the crumbling Empire.
A Roman mob stoned him to death.