Final answer:
The year that saw the rise and fall of three different Roman emperors was 68-69, also known as the 'Year of the Four Emperors.'
Step-by-step explanation:
The year that saw the rise and fall of three different Roman emperors was 68-69. This period is sometimes referred to as the 'Year of the Four Emperors.' After Nero's death in 68 CE, four different generals assumed power within a year, resulting in a period of instability and rapid turnover of leadership.