2-300 years ago it was the norm.
Actually, the absolute heyday of racism and white supremacy in USA was probably just about 100 years ago.
However, it was based not on Biblical explanations, but on the science of the time, which was pretty uniformly outspoken about the inequality of the races and the superiority of the white race.
The only real scientific argument over this at the time was about which branch of the"white race" was superior to its other branches. Oddly enough, each of the scientists generally determined that it was his own branch. :)