Lately I have come across what appears to be a Latin abbreviation, "A. O. R.," on several title pages of books from the eighteenth century. The abbreviation may have to do with the date, perhaps? Here's an image of what I'm talking about. If you know or have a thought, please share.

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1 Answer 1


According to this list of abbreviations A.O.R. stands for Anno Orbis Redempti, roughly "in the year since the world was redeemed". It seems to be one of an interesting set of obsolete synonyms to Anno Domini, including Anno Christi, Anno Post Christum Natum, Anno Salutis, Anno Salutis Reparatae, Anno Humanae Restaurationis...

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    That must be it. Excellent. And plus a billion for linking to that list. Commented Jun 2, 2020 at 17:36
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    @TKR My first guess is that the participle in Anno Orbis Redempti is dominant, right? But cf. Anno Salutis Reparatae and Anno Salutis. This reminds me of the question on how obligatory the so-called "dominant" {participle/predicate} is. Cf. latin.stackexchange.com/questions/9412/…
    – Mitomino
    Commented Jun 2, 2020 at 18:48
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    Odd that it isn't equivalent to AD +33. Commented Jun 3, 2020 at 3:08
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    @chrylis-cautiouslyoptimistic- I recall reading somewhere that AD 0 is used both for His birth and death, leaving those 33 years missing. If this is true, it’s somewhat ironic that the date system built around Him excludes His life! It would also explain why it’s not equivalent to AD 33. (As another aside, I think His birth is now considered closer to BC 8, not 0)
    – Tim
    Commented Jun 3, 2020 at 8:26
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    @Tim: I don’t think those years were ever missing in anyone’s version of the system, or that (once the system was established) people disagreed on the number of their current year due to this point. It’s just that people sometimes misunderstood the system, thinking that AD 0 was intended to refer to Christ’s birth or crucifixion — so most people would said “A.D. 1700 means 1700 years since Christ’s birth”, some would have said “A.D. 1700 means 1700 years since Christ’s death”, but both would have agreed that the current year was 1700 and that the year before 1 AD was 1 BC. Commented Jun 3, 2020 at 13:04

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