RE: The Almost Forgotten Roman Emperor !

Surprising indeed, since the Romans used to write down a lot of what happened politically. But may be this guy was kind of a one hit wonder and his fame was short lived - perhaps literally. And of course, also this writing would be almost 2000 years old, and not everything has survives this long time.
Sometimes the expression "during the time of the Romans" can be misleading, and one assumes its a few hundred years. But in fact its almost 1000 years, and a lot of stuff happened and a lot of people came and went in that long time.