Isis.) When Iphis was thirteen Ligdus betrothed her, still in her male guise, to Ianthe, and the two fell in love. Telethusa attempted to postpone the wedding in view of the embarrassing situation, but eventually Isis once more came to the rescue and changed Iphis' sex into a boy so that all was well.
None of this androgynous story seems to be reflected in the name of Iphis, which presumably simply means 'mighty', 'strong', from iphios. However, Ovid tells us (the story is, as might be expected, one of his Metamorphoses) that when Iphis changed sex 'her strength increased' and 'she showed more energy than a woman'. So her strength thus lay in her new-found manliness.