Background
Hennis was born in Hildesheim.
Hennis was born in Hildesheim.
In 1960, he became Professor at the Pedagogical College of Hannover. In 1962, he became a Professor in Hamburg, and in 1967 at Albert Ludwigs University of Freiburg, where until his death he was a Professor Emeritus. He died, aged 89, in Freiburg im Breisgau.