1770: AD, BC, and ACN Oct 19, 2019

Most people will be familiar with AD and BC use for writing years, but it may strike you as strange that one is Latin, Anno Domini (in the year of our lord), and one is English, Before Christ. Indeed, while this notation is fairly old—from the 5th century but not popular until the 9th—the earlier version of BC was 'ante Christum natum' (before Christ's birth). This is sometimes abbreviated 'a.Ch.n' or 'ACN', but this is not as popular now, or even always historically; St. Bede used a different phrase for instance.

More on this tomorrow.

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