Even 100 years ago copyright terms were pretty long: as long as you remembered to renew you got 56 years. Obviously the current life-plus-even-more term is a m

Even 100 years ago copyright terms were pretty long: as long as you remembered to renew you got 56 years. Obviously the current life-plus-even-more term is a more recent change in the US, but the Berne Convention (not yet joined by the US at the time) required minimum terms of life plus 50 years starting in 1908.