Passage 3.19.11
ὃν δὲ οἶδα λέγοντας Κροτωνιάτας περὶ Ἑλένης λόγον, ὁμολογοῦντας δέ σφισι καὶ Ἱμεραίους, ἐπιμνησθήσομαι καὶ τοῦδε. ἔστιν ἐν τῷ Εὐξείνῳ νῆσος κατὰ τοῦ Ἴστρου τὰς ἐκβολὰς Ἀχιλλέως ἱερά· ὄνομα μὲν τῇ νήσῳ Λευκή, περίπλους δὲ αὐτῇ σταδίων εἴκοσι, δασεῖα δὲ ὕλῃ πᾶσα καὶ πλήρης ζῴων ἀγρίων καὶ ἡμέρων, καὶ ναὸς Ἀχιλλέως καὶ ἄγαλμα ἐν αὐτῇ.
I shall now mention a tradition concerning Helen which I know the people of Croton relate, and which the inhabitants of Himera also agree with. There is in the Euxine Sea an island located near the mouths of the Ister sacred to Achilles. The name of this island is Leuke, its circumference is twenty stadia, and it is entirely covered with trees, filled with wild and tame animals; and upon it there is a temple dedicated to Achilles and a statue of him.