Original sentence: Josephus in Jewish Wars, chapter V, verse 235, wrote "τὰ ἱερὰ γράμματα: ταῦτα δ' ἐστὶ φωνήεντα τέσσαρα" ("...[in which was engraven] the holy letters: and they are four vowels"), because Hebrew י and ו, even if consonantal, would have to be transcribed into the Greek of the time as vowels
Edited sentence: Josephus in Jewish Wars, chapter V, verse 235, wrote "τὰ ἱερὰ γράμματα: ταῦτα δ' ἐστὶ φωνήεντα τέσσαρα" ("...[in which was engraven] the holy letters: and they are four vowels"): this probably means "i-a-u-e" as a Greek approximation to "Yahweh"