Hmmm... missed it by that much.
No problem. History has a very odd way of getting foreshortened as it gets farther in the past. Perhaps the most obvious example of this is the way people talk about various events “in the time of ancient Rome” as contemporaneous when they are actually 400 or 600 years apart.
Our world has changed a great deal in 500 years, and so did that of the Romans. The excesses of Nero and Caligula had very little to do with the Fall of Rome.