Explanation: 69 AD (nice) was known as the Year of the Four Emperors, due to there being, well, four Emperors inside of a year. The Emperor Galba assumed power when Nero was ousted by the Senate in 68 AD, but he was overthrown by Otho - Otho, in turn, was defeated by Vitellius, and Vitellius was quickly destroyed by Vespasian, who went on to have a stable reign.