Adolf Hitler's father was authoritarian, strongly political, thought of himself as above others and had a lasting impact on his son, a German historian has claimed. Roman Sandgruber, professor emeritus at the University of Linz, says he made the discoveries after studying a never-before-seen trove of 31 letters written by Alois Hitler to the man who sold him a farm in 1895 - around Adolf Hitler's sixth birthday. Sandgruber argues ...