From the annotations to Spenser’s Faerie Queene (does one italicize “Faerie Queene,” or put it in quotes? or inverted commas? which are the same thing? why did I end the preceding phrase with a question mark?) in the Norton Anthology of English Literature:
That Spenser contemplated (as he proceeds to indicate) a poem four times as long as the six books we now have rather staggers the imagination.
I was already feeling slightly pretentious for slogging through Spenser over tea. That, one of the most rarefied annotations I’ve ever read in a modern edition of something, totally just upped the ante.
Emily Rutherford 
As an English major my instinct is to put it in italics. But I’m not absolutely positive, I’ve never written on it so I’ve never had need to think about it really.