OMFG will you *look* at how Goujun says 'you' to Konzen? Kiden. Written with the kanji for 'honourable' and 'lord, palace.' OK, OK, Goujun is punctilious indeed.
(To be borne in mind: army Goujun doesn't 'know' bureaucracy Konzen in any formal sense, hence polite usage, especially as he's trying to reason with the man. The J/J says 'male form of address to someone of equal (or lower) rank, used in letters' (J: now) 'meaning you (anata)'. Yet another of those polite circumlocutions that for once didn't descend into the gutter. Also FWIW he calls Kenren kimi at first meeting. Wish I could find my later eps to see what he says -if anything- after being taken hostage.)
And oh for a J/J dictionary that gives you earliest usages, as the OED does.