Alois Hitler, Adolf Hitler's father, was born Alois Schicklgruber on June, 7 1837. The reason he was born Schicklgruber was because his mother, Maria Anna Schicklgruber, was unmarried so he took his mother's name. Some time later, Johann Georg Hiedler married Maria Anna Schicklgruber, but Alois remained Schicklgruber until he was 39 years old, when he had his name legally changed - to Hitler, a variation of Hiedler. It is not clear why the name became Hitler from Hiedler, but Germany may have been standardizing names at the time.

There is an old, tasteless joke about this whole episode. If Adolf's father Alois had remained Schicklgruber, Adolf would have been Adolf Schicklgruber, and it's hard to imagine the whole German nation going "Heil Schicklgruber." The Third Reich might never have happened had Alois Hitler never changed his name.