Geoffrey Chaucer,
Chaucer's Works, Volume 5 — Notes to the Canterbury Tales
“ The 'exaltation' of a planet is that sign in which it was believed to exert its greatest influence; and, in accordance with this, the old tables call Taurus the 'exaltation of the Moon,' and Libra the 'exaltation of Saturn.' These results, founded on no reasons, had to be remembered by sheer effort of memory, if remembered at all. I have no doubt, accordingly, that Chaucer (or his scribes) has made a mistake here, and that the reading should be 'Saturnes,' as proposed by Tyrwhitt. ”
