This is a tangent, but in Latin that "of" is not included in the re; it would have to be marked on whatever noun is governed by the "of" in English. Including the "of" makes the English translation better, but slightly less literal - in the most technical possible sense, the "of" is implied rather than explicit.

In English it's easy to indicate that some word or phrase requires an argument marked with "of" by just including the "of" when you cite the word/phrase. In Latin this can't be done. A dictionary (aimed at modern students) would say something like "res +gen" to note that an expression requires an argument in the genitive case. I don't know how Latin speakers would have described this, but the need must surely have come up.

Tying back to my earlier observation, it might interest you to know that the word "of" is derived from "off". The reason is kind of funny: off is a (correct!) translation of the Latin preposition de. de doesn't mean "of", but it does mean "off". Latin has no preposition for "of".

However, in Romance, the case system of Latin was lost, and de was repurposed into a genitive marker. That's why it means "of" today in Spanish, French, etc. I assume this had already happened by the time English translated it as "off", and that's why the genitive particle "of" developed, but I don't know for sure.