I feel I should point out that if this was his claim, that Jerome mistranslated metanoia (μετάνοια) as do penance and "it had to be corrected by the Wycliffe and the Lollards as, "repent"", then that seems to me to be simply wrong.
If Wycliffe was the one who corrected the mistranslation to mean repent, then
why did he make that same supposed mistranslation? The Wycliffe New Testament (translated from the Latin) quite consistently translated metanoia as penance. I used a concordance to look up every instance of metanoia in the New Testament, then looked up how Wycliffe rendered those verses.
Have a look. He repeatedly used penance. So how in the world did Wycliffe "correct" this alleged mistranslation if he was clearly following it?
Now we turn to the Latin Vulgate itself. Every instance of metanoia in the Greek New Testament, I believe, is translated as poenitentia (variant spelling of paenitentia) in the Latin. Metanoia means repentance. And paenitentia... means repentance. This is not a mistranslation, obviously, to translate a word into a word that means the same thing. Also, Jerome didn't translate the New Testament part of the Latin Vulgate. He just
edited already-translated Gospels, and didn't do anything with the rest of the New Testament (which were edited by unknown people). The translation was the Old Testament, where he translated directly from the Hebrew into the Latin, rather than translating from the Greek Septuagint (translated from the Hebrew) as prior translations into Latin did. Anyway, it looks like translating metanoia as poenitentia was done in the translations prior to Jerome, as earlier Latin writers quote the applicable verses using that word (e.g. Tertullian, writing in Latin and quoting Matthew 3:8 in Against Hermogenes, uses that word--clearly this was not from Jerome, who was not even born at that point).
So no issues with the Latin Vulgate on this. But wait, someone might say. Maybe the Latin Vulgate is cleared, but what about translations from it? Doesn't the Douay Rheims Bible--the most notable translation of the Latin Vulgate--say "penance" in these cases? Shouldn't it use repentance? Well, while paenitentia can mean repentance, it can also mean penance in the normal English sense (an act of self-punishment used as an outward sign of repentance). However, I would submit that this is not the result of them choosing the wrong meaning from the Latin, but rather that they translated accurately in the Douay Rheims (in both the original translation from around 1600 and the better-known revision by Challoner around 1750). This is because of the time they were translated.
In modern English, the word penance, aside from its usage in the "Sacrament of Penance", means, as my dictionary nicely explains, "voluntary self-punishment inflicted as an outward expression of repentance for having done wrong." However, penance can also mean simple repentance or regret without inherently implying the aforementioned definition. This meaning has fallen out of use, however, to such an extent it isn't listed in the dictionary I just cited. But the Oxford English Dictionary does offer as one of its definitions "Repentance, penitence; amendment of one's life. Now rare." The Douay Rheims translation(s) were done well in the past, when this meaning was more frequently understood. I suppose they could have still used repentance, but given the word penance literally comes from paenitentia, it makes sense to render it as penance if it still shared the same meaning. As noted, since then that meaning has fallen out of favor, but I notice that more recent translations from the Latin Vulgate, such as the Knox Bible or Confraternity Bible (both from the mid 20th century), use "repentance", keeping up with the shifts in the English language. For comparison, the Douay Rheims (again, circa 1750) rendered Matthew 3:8 as "Bring forth therefore fruit worthy of penance." The Knox Bible a renders it "Come, then, yield the acceptable fruit of repentance" and the Confraternity Bible (well, one of them, I think there are several versions) says "Bring forth therefore fruit befitting repentance."
One can, of course, assert that proper repentance involves penance anyway, as you argue--but even if one wants to draw a distinction between the two, I don't think there's any mistranslation here.
