Duc de Saint Simon
I hope the great diarist of Louis XIV court: the Duc de Saint Simon will be featured in Season 2. Unfortunately he wasn't in Season 1.
The series opens notionally in 1667; Louis duc de Saint-Simon was born in 1675.
That means nothing, of course - it wouldn't surprise me to see him pop up in season two, pausing after writing the day's events, pensively toying with his quill, bare-chested while the camera pans lasciviously over his bulging deltoids.