Portraits of dead guys

This (to the left) is my favorite portrait of the greatest of men; Spinoza. The artist does a good job capturing Spinoza's famous tranquility without making him look like a pansy. He appears confident, and relaxed, like a european aristocrat with a jewish face.
I always wonder what these famous people actually looked like. I saw a show on the discovery channel where some scientist was trying to recreate George Washington's face as a young man. All of our drawings of him are after he lost his teeth and his hair and so our image of him is kind of like our image of our grandparents--we have no idea the type of presence he had when he was in his prime. When the guy showed a computer image of him with a strong jaw line, red hair, and straight back, he looked like a total bad ass, not like some gummy coot looking for dentures. Seriously, the picture of him as a strong young man sort explained why he was always called a natural leader, and why everyone assumed he would lead the revolutionary army. He looked like a total hardcore warrior.

I was also thinking, since portraits are usually pretty generous to the subject (its not as if someone was going to paint an unflattering shot of Napoleon) how ugly were some of these guys? Look at this drawing of Descartes. He could not have been a pretty man.