Capitalization

Q. I’m editing a Regency-era romance, and there are several references to the Secretary of Foreign Affairs, shortened to Foreign Secretary in some places and Secretary in others. I’m aware of Chicago’s preference for lowercase in such circumstances. I find myself using lowercase for the prime minister with ease, but the secretary is giving me pause. I’m worried about creating confusion with the modern idea of clerical secretaries.

A. In a Regency-era romance where the full title and partial title of the secretary of foreign affairs appear in several places, you can probably trust readers to understand that this character is not an administrative assistant in the office of a modern start-up. (If not, capitalization should be the least of your worries.)