It all has to do with the Septuagint.
The Septuagint was the translation made of what is now the Old Testament into Greek, by apx. 70 translaters (hence the name) from the original Hebrew, in Alexandria, several centuries before the birth of Jesus.
The first Catholic translations (Douay, Confraternity) used the names of the OT books as they were in the Septuagint. Hence, there were 4 Books of Kings, rather than 2 of Kings and 2 of Samuel. Otheer differences included Paralipomenon for Chronicles.
Names were also rendered as per the Greek. Elijah was Elias; Noah was Noe; Joshua was Josue. Also, the Psalms were numbered differently than in recent translations, although there were always 150 of them. (There is a Psalm 151 in an appendix to the Greek canon, but it’s not canonical anywhere that I know of.)
Some of the Septuagint names still appear in some translations along with the more recent renderings, usually as an “or” entry.
Sometimes it can be fun to refer to Holy Scripture passages by the old names to confuse argumentative or obnoxious Catholic baiters, but that’s really not something I do any more (and probably shouldn’t have done, years ago, in the first place).
Blessings,
Gerry