Q. CMOS 13.7 recommends silently correcting typographic errors while retaining capitalization of older works. I am writing a book with numerous quotations from archival sources from the nineteenth century. Does that count as old? These sources seem to have idiosyncratic rules about capitalizing empire following proper names, such as “the Roman empire.” Is the text old enough to preserve that error?

A. You seem to have misunderstood the spirit of 13.7. The point is to try to distinguish between (a) modern sources, where typos and bizarre spellings are assumed to be unintended errors, and (b) writings that were published (or transcribed for print) before the time when consistency in spelling was a goal. There’s bound to be some overlap in the two—it’s not as though there’s a date when “old” turned into “new.” So try to think in terms of “intended” and “unintended” spellings. CMOS is saying that it’s fine to correct an unintended typo or two. We’re not saying that it’s OK to change the character of a document by changing all the old-fashioned spellings and stylings into modern ones. And incidentally, Chicago style uppercases Roman Empire (per CMOS 8.51).