In Windsor Castle you can view the original sketches that Holbein made in preparation for his paintings. And you should, for they are simply exquisite.
Using the minimum of detail and effort, Holbein somehow captures the essence of these people, warts and all. These pictures were never meant to be seen, yet they seem incredibly alive. If you look closely enough at these drawings of people from five hundred years ago, you can almost smell them.
View more of his sketches HERE.