We largely have Christianity to thank for our faltering modern belief that human life is sacred. The ancients took a much more casual approach. Unwanted babies were abandoned to die or be rescued by strangers: like Romulus and Remus, Rome’s mythical founders, who were raised by a wolf.
Much as new lives were not automatically worth preserving, taking your own life in the ancient world wasn’t automatically bad either. Socrates’ decision to drink hemlock rather than face exile, was deemed honourable by many ancient philosophers.