Year of the Four Emperors

The Year of the Four Emperors, AD 69, was the first civil war of the Roman Empire, during which four emperors ruled in succession, Galba, Otho, Vitellius, and Vespasian. It is considered an important interval, marking the change from the Julio-Claudians, the first imperial dynasty, to the Flavian dynasty.

Source: Wikipedia — Year of the Four Emperors (CC BY-SA 4.0)