Is "attend on" correct?

I have read several books by Lois MacMasters Bujold in which she uses the verb "attend on." She seems to use it to mean that a subordinate should attend his or her superior: for instance, "Lord Williston, attend on me in my chambers!" And she seems to use it in situations where she wants to set a somewhat archaic mood.

My question, was "attend on" ever used in this way, or is this something that Bujold made up as a kind of variation on "Wait on," — as in, "Lady Braknell is not available, she waits on the queen today."