If you're writing a period piece, you have to really put your characters in their time frame. You have to know about the music, books and politics of the day. And you might be writing a story that takes place hundreds of years before anyone you know was ever born. So under those circumstances, is it all right to use historical figures in your fiction?
Expiration Dates
Anything ever written by Jane Austen can be purchased for free by you today. Any publishing company can print out copies of Jane Austen books, and they don't have to pay anybody any royalties for what they sell. It's because Jane Austen has been dead for so long that all her copyrights have now expired. Anyone can publish and use her books for free these days.
So what's the expiration date on a personality? If Jane Austen's copyrights are expired, does that mean that I can make her a character in my newest book?