Jürgen Prochnow was 28 in Unternehmer when he played the character 'Arnold'.
That was over 53 years ago in 1970.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 82, and has starred in 116 movies in total, 114 of those since Unternehmer was released.
In Unternehmer, I think Jürgen Prochnow looks: