These lovely ladies are both Phaeton's sisters and the daughters of Clymene and Helios. (Get it? HELIades.) They don't actually do too much until the very end of the tale, when they gather at the banks of the River Po and mourn the loss of their brother, who's fallen to his death in the waters. The Heliades are so sad that they turn into poplar trees. (What, you've never seen a sad person turn into a tree? Maybe you need to get out more.) It's said that even as trees they cry, but their tears are golden drops of sap that harden into amber. The Heliades were the stars of a lost play by Aeschylus that people say told the story of Phaeton. We wonder if they ever cry about the loss of the play about them too.