Pandion was a king of Athens who had 2 daughters, Procne and Philomene. In one of the wars, Pandion had to call upon Tereus, the ruler of a neighbouring nation, for help.  As a sign of gratitude for helping him win the war, Pandion offered Procne as a wife to Tereus and they later had a son named Itys.  After some years, Procne grew lonesome for her sister and asked Tereus to bring Philomene from her father's place. On route home with Philomene, Tereus began to lust after her. He raped her, cut off her tongue and then abandoned her.  Tereus told Procne that her sister had died during the voyage. But Philomene managed to weave her story into a robe that she sent to Procne. On learning what Tereus had done, Procne plotted revenge on her husband. She promised Tereus a wonderful dinner,  then killed her son and served him to his father. While Tereus was enjoying his dinner, Procne went for Philomene and the 2 sisters fled. When Tereus discovered the horrible plot, he took up his axe, went after the women and soon overtook them. Procne and Philomene prayed to the gods for help and were turned into birds to fly away. Procne became a nightingale, sorrowfully crying "itu, itu" , the name of her son. Philomene became a swallow, a voiceless bird. Somehow, Tereus was also turned into a bird, a hoopoe. Some accounts say Tereus was turned into a hawk. The osprey, Pandion halieatus, is sometimes known as the fish hawk.