What's a historical fact that no one knows?

In ancient Athens, it was very common for a couple to take a newborn baby girl out in the wilderness and leave it to die—an act they called “exposing” the baby. “Everybody raises a son even if he is a poor,” one Greek writer wrote, “but exposes a daughter even if he is rich.”

In Rome, this was just as common, especially in poor families. We have records of a lower-class Roman writing to his wife about her pregnancy. “A daughter is too burdensome, and we just don’t have the money,” he told her. “If you should bear a girl, we’ll have to kill her.”

Even in Egypt, which gave women comparatively equal rights, the poor often left kids to die. “If you have the baby before I return,” one letter shows an Egyptian man writing his wife, “if it is a boy, let it live; if it is a girl, expose it

Time changes everything.