But maybe I'm wrong and there is another example for such an unusual case.
Post if you can imagine one or what you think about this.
PS: Maximilian Schell was also the first German speaking actor to win the Oscar for best actor since 1929, which is also the year of the first Oscar ceremony ever.
PPS: At this time he was also the second youngest actor ever to win the Oscar after Marlon Brando in "On the Waterfront". Today he is the fourth youngest after Adrian Brody, Richard Dreyfuss and Marlon Brando.