Polyxena

With Hecuba, wife of King Priam of Troy, Apollo had a son named Troilius. An oracle prophesied that Troy would not be defeated as long as Troilius reached the age of twenty alive. He and his sister, Polyxena were ambushed and Troilius was killed by Achilles, who later fell in love with Polyxena. During a truce, Achilles was killed visiting her.

The ghost of Achilles appeared to the survivors of the war, demanding Polyxena, the Trojan princess, be sacrificed before anybody could leave. Neoptolemus did so.