Alois was the illegitimate son of Maria Schicklgruber, who had married Johanna's paternal uncle, Johann Georg Hiedler on 10 May 1842.
Alois would claim in later life that Johann Georg Hiedler was not his stepfather, but in fact his biological father, and he was officially declared Johann's legitimate son in 1876, although this claim as to Alois's real paternity has remained the subject of much debate among historians.Klara and Alois had six children.
The fourth of these was Adolf Hitler (born 20 April 1889).
Only one other of Klara's children – the youngest, named Paula – survived into adulthood.
Klara's husband, Alois, also had two other children, Alois junior and Angela, from his second marriage (to Franziska Matzelsberger).