Philomela was the daughter of King Pandion of Athens. The king gave Philomela's sister, Procne, in marriage to King Tereus of Thrace after the latter had helped him in his war against Thebes. After a while Procne began to miss her sister and asked her husband if he would allow her to visit. Tereus consented,  returned to Athens, but conceived a passion for Philomela himself. He persuaded King Pandion to allow the girl to return with him to Thrace, but instead of taking her to her sister, he raped her, cut out her tongue and confined her in a shed in the forest under guard, telling Procne that she had died. Philomela remained a prisoner for a year, during which time she wove a tapestry (the web in Arnold's poem) telling her story, and thereby informed Procne of what had really happened. Reunited, the two sisters plotted their revenge: they killed Itys, Tereus' son by Procne, and served him up to his father in a stew. When he discovered what he had been eating, Tereus chased them, but they transformed into birds and escaped.