From the Fragments of the Greek Historians–Mythical traditions record that Thetis hid Achilles at Skyros to prevent him from getting taken to fight at Troy where she knew he would die. Most retellings of this focus on how Odysseus tricked him into revealing himself. But it turns out Achilles also took on a girl’s name while he was there.
BNJ 57 F 1 Ptolemy Chennos, Novel History, Book 1 Photios, Bibliotheca 190, 147a18
Aristonikos the Tarentinian reports that Achilles, when he was living among the girls at Lykomedes’ place, was named Kerkusera, and Issa and Pyrrha. He was also called Aspetos and Promêtheus.
ὡς ᾽Αχιλλέα μὲν ᾽Αριστόνικος ὁ Ταραντῖνος διατρίβοντα ἐν ταῖς παρθένοις παρὰ Λυκομήδει Κερκυσέραν καλεῖσθαί φησιν καὶ ῎Ισσα καὶ Πύρρα· ἐκαλεῖτο δὲ1 καὶ ῎Ασπετος καὶ Προμηθεύς.
The names he takes on surely deserve a little more contemplation. Why did he also have male names while he was there?
Ken Dowden, in his commentary on this fragment, provides the following explanation of the female names:
“The name Pyrrha (red-head, like Pyrrhos the alternative name of his son Neoptolemos) is also found in Hyginus, Fabulae 96. The name Kerkysera is held to be a ‘joke’ (i.e., of Ptolemy Chennos) by A. Cameron, Greek Mythography in the Roman World (Oxford 2004), 141, presumably by association with κέρκος (a tail or penis). M. van der Valk, Researches on the Text and Scholia of the Iliad (Leiden 1963), 369 n. 228, regards the name as corrupt–it should, according to him, be Κερκουρᾶς (Kerkouras) ‘he who urinates by means of his tail’. Even if this is right, it does not, of course, show that the name was invented by Ptolemy Chennos. Cameron, Mythography, 141, views Issa as an out-of-place Latin term of endearment. But it appears in Greek as the name of a Dalmatian island and, more appropriately to Achilles, of a city on Lesbos (named after a daughter of Makar, Steph. Byz., s.v. Issa). ‘There is also a feminine form Issas on Lesbos found in Partheniosin his Herakles’ (ἔστι καὶ θηλυκὸν Ἰσσάς ἐπὶ τῆς Λέσβου παρὰ Παρθενίῳ ἐν Ἡρακλεῖ) according to Steph. Byz. ibid. A real Aristonikos, given the range of possible dates (see Biographical Essay), might well have been reading Parthenios, or even vice-versa.”
This text is from Brill’s new Jacoby, a collection of the Fragments of the Greek historians