When to drop AD and BC from dates?
I see some texts using AD and BC or BCE and CE. But other texts just have the date, like 1992 and it is understood. Is there a rule of thumb for when to add these prefixes? I'm using Chicago-Turabian.
When to drop AD and BC from dates?
Well as usual the answer is can the reader understand the text if you drop them. If you were talking about the G20 meeting in 2018 I think the meaning is clear even if you do not use A.D. If you were talking about the evolution of military tactics used by Roman Centurions, then I am sure you would need to include B.C. or A.D.