Dumb question as I have never read Hitler's book. When did Far Eastern fighting styles migrate to the West? I would have said the 50's or 60's, but I don't know.
Theodore Roosevelt practiced jiu jitsu. And he was not the first one. There was also bartitsu, a mixed martial arts system developed by a Englishman named E.W. Barton-Wright, that combined judo, boxing, canne de combat, savate and Swiss wrestling. This was in 1898. But the real popularity began with returning servicemen after WW2, and it really picked up in the 60s and 70s.