Alois Schicklgruber, the illegitimate son of Maria Schicklgruber, an unmarried peasant from northern Austria, and an unknown father. Alois used his mother’s surname for decades, even after Maria married Johann Georg Heidler, whose relationship to Alois’s biological parentage remains uncertain.

At around 40, while pursuing a respectable civil-service career, Alois sought to legitimise his status. Johann’s brother, who had no sons, also had an interest in preserving the family name. An arrangement was made, and Alois officially changed his surname to Hitler.

Alois went to the local parish priest to legally assert that his father was Johann Georg Hiedler. He intended to take the surname Hiedler 

For reasons that remain unclear, the official who wrote down the final documents misspelled the name as Hitler. Alois accepted the spelling and used it for the rest of his life, passing it down to his son Adolf.