Question: In Judith in Vulgate, why does Jerome transliterate the name "Arphaxad" with 'ph', but he transliterates "Holofernes" with an 'f'?

By the time of Jerome, both 'f' and 'ph' were the same sound, the English /f/, right? And Greek letter φ was pronounced /f/ as well at the time, right?

Regardless, they were arguably the same sound given that Jerome was transliterating φ from the same Greek text two times.

Answer: 
### Both of these names are older than the Book of Judith, and come from different places.

*Arphaxad* is a transcription of Hebrew אַרְפַּכְשַׁד (*ʔarpakšad*), which appears in Genesis: a minor character who's only mentioned in genealogies.

*Holofernes*, on the other hand, is the Persian name of a Cappadocian ruler mentioned in several historians (as *Holophernes*, *Olophernes*, *Orophernes*); I haven't been able to find the actual articles, but I've found citations for Justi 1895 and de Jong 1999 linking this to Iranian \**Varufarnah* "having wide glory" (related to Avestan *Xvarenah* "Glory (deity)")

Jerome, as a rule, stuck very closely to the Greek of the Septuagint when transcribing Hebrew names; that's why we see *Jose**ph*** for Ἰωσή**φ**, even though the Hebrew of the time had an `/f/` at the end.

But *Holofernes* wasn't a Hebrew name, and presumably it had been previously transcribed into Latin—the only surviving mentions I could find are written in Greek, but the historical Holofernes lived during the Hellenistic period and made treaties with Roman rulers. So instead of just copying out the Greek and getting something like *Olophernes*, Jerome went with the Latin transcription he was familiar with.
One possible avenue is that Jerome is hearing a difference in the original Hebrew/Aramaic. In Hebrew, Arphaxad is spelled אַרְפַּכְשַׁד. The פַּ has a dagesh, which means that it is pronounced as a bilabial plosive, *p*. With Judith, [Jerome says](https://www.tertullian.org/fathers/jerome_preface_judith.htm#4) he is translating from "Chaldean" (i.e. Aramaic), not Greek. So it doesn't matter then what the Greek is doing; if the Aramaic preserved the plosive /p/ for Arpaxad and the fricative /f/ for Holofernes, that's likely what Jerome followed, at least as best as he understood it.

Possibly too he knew the name before his translation from other sources, as Draconis mentioned. The standard way of writing it in Latin would have been to follow the Greek transcription of Olophernes (same name, different person), so it is uncertain from the evidence available why he would have chosen to forego the -*ph*- and write -*f*- instead.

Jerome is not entirely consistent in his transliteration, at least not regards with the Masoretic vocalization. In the name *Ephraim*, Jerome spells it with a -*ph*- even though the peh lacks the dagesh, yet he spells the name *Phineas* (which has a dagash) with an *F-*, *Finees*. There is no distinction between phi /ph/ and phi /f/ that Jerome would have been hearing, so it is again unknown why he chose to transliterate certain words one way and others another way.

Interestingly, this is not restricted to Hebrew names. In the *Prologus*, he writes the name *Xenofontis*, whereas it's unambiguously [*Xenophontis*](https://latin.packhum.org/search?q=xenopho) in Classical sources. I suppose to be thorough one would have to check the *apparatus criticus* of enough of those references to see if, when, and where there was variation, but at least in the UBS edition, there is no mention of *Xenohpontis* in the manuscripts.

So, even if Draconis' answer might be technically correct (although we can't be sure), it doesn't explain *Finees* or *Ofni* v. *Ephraim*, especially since in some places the latter is spelled *Efraim*. Possibly some of it comes from Old Latin, possibly some from the Greek v. historical texts, possibly from learned sermons of the day, but in the end it doesn't look very consistent to me.

Which is funny, of course, since you can also find Holophernes and Holofernes in English papers and books, sometimes interchangeably by the same author.

Short answer is: We just don't know, but it is consistent with Jerome's inconsistency. **And at the end of the day, it just might come down to only to inconsistencies.**