Good advice from Erasmus and Colet
From De ratione studii (1511), written by Erasmus and John Colet, setting out plans for the studies at St Paul's School: a teacher should not be "content with the standard ten or twelve authors, but would require a veritable universe of learning".
It seems to me that sums up the real arrival of the Renaissance, or if you prefer humanist learning, in England.
And it ties rather neatly with a recent IHR seminar that I hadn't got around to writing up: "Humanism, reading and political writing", presented by Daniel Wakelin. It was in the late medieval seminar, so the Latin went straight over my head, and it was a bit earlier than I'm now really looking at, 15th-century rather than 16th, but it was interesting, the main argument being (as I understood it) that while humanism has been accused of being an "apology for princes", it was merely a technique and approach that could be used for a variety of political purposes.
(Quote from The Cambridge Companion to English Literature 1500-1600 A. Kinney, ed. p. 7. Pace earlier discussions, from what I've read thus far this is an unusually lucid and sensible volume; technical terms are used and explained, but not thrown at the reader as though this were a paintball contest - a refreshing change from some of the other "English studies" stuff I've been reading recently.