One point, though, sparked an idea; Paracelsus, it turns out, took that name because he was claiming to be as good as--or perhaps better than--the Roman physician Celsus. Why be "as good as" Celsus? Because the people of that time believe the Romans were "better" than they were--they'd built so many impressive things, and conquered the known world; Western Europe grew up in the shadow of Rome. And somehow this got transmuted into a belief in the "greatness" of invididual Romans.
Looking at this from the other side of the "greatness" of modern Western Civ it's clear that individuals now are no "greater" than they were 500 years ago, or 1000 years ago; it's the accomplishments of many that makes our greatness. So when some politician, or some scientist, or some general, is called "great"--look at the claim skeptically.