Greek Self-Sacrifice: Agraulos

Athens was at one time involved in a long-protracted war, and an oracle declared that it would cease, if some one would sacrifice himself for the good of his country. Agraulos came forward and threw herself down the Acropolis. The Athenians, in gratitude for this, built her a temple on the Acropolis, in which it subsequently became customary for the young Athenians, on receiving their first suit of armour, to take an oath that they would always defend their country to the last.

It is, of course, one of three vastly different stories of her death. The other two involve opening a box she wasn't meant to open and then either killing herself (jumping from the Acropolis) or being killed (turned to stone) over that crime. Any of the above.