While tha 36x24 frame dates to the original Leica, I believe the 3:2 aspect predates that significantly as the some of the early Kodak box cameras shot 6x9cm on

While tha 36x24 frame dates to the original Leica, I believe the 3:2 aspect predates that significantly as the some of the early Kodak box cameras shot 6x9cm on 120 film.