I was reading this excellent post from Dial B for Blog about the creation for the Batman, and at the end of the post I read that the inspiration for the Joker came from a 1928 silent film called "The Man Who Laughs." You can watch the film in it's entirety on YouTube. The plot of the story is King James takes revenge on a lord who offended him by having his son's face surgically altered so he would always appear smiling. I found the film to be quite disturbing and I couldn't watch the whole thing. I don't reccomend watching it if you are prone to nightmares.
I don't like it when comic book characters have their origins changed when they are transferred to film. Comic Book Joker got his smile because of falling into a vat of acid. The Joker from the Dark Knight had his face mutilated, just like the character from "the Man Who Smiles." (Which first appeared as a book published in 1869.) So, who played the title character Gwynplaine in "the Man Who Laughs?"
His name was Conrad Veidt. He died relatively young at the age of 50, and like Heath Ledger he caused a stir early in his career by playing a gay man in a film. (probably the first portrayal ever)
Veidt also appeared in Magnus Hirschfeld's pioneering gay rights film Anders als die Andern ("Different from the Others", 1919), in which he played what is likely the first gay character written for the cinema, and in Das Land ohne Frauen (1929), Germany's first talking picture
What really grabbed me was his date of birth and death. He was Born on Jan 22 1893, and he died on Apr 3 1943. Heath Ledger was born on April 4 1979, and died on Jan 22 2008.