Celebrities spend a lot of time signing autographs, but besides personal value the ones that really end up being worth lots of cold hard cash are the rarest ones. In today's day and age it's hard to get through a single day sometimes without signing for a credit card purchase or something else, but hundreds of years ago things were different. Even for somebody who spent most of his time with a quill in his hand.

For all the writing William Shakespeare did he apparently didn't sign his name very often. Today there are only six of the playwright's known authenticated signatures in existence, which helps make his John Hancock one of the most valuable in the world. One can be found on a conveyance for a house in London, one on a legal deposition, one on his mortgage documents, and three in his will. And any one of those is worth $3 million, seriously.