And then there's all the callbacks to those. Here's a few lines of Keats I read recently:

...but to that second circle of sad Hell

Where in the gust, the whirl-wind, and the flaw

Of hail-stones, lovers need not tell

Their sorrows; pale were the lips I saw

Pale were the lips I kissed, and fair the form

I floated with, about that melancholy storm.

For those keeping score at home, that's Keats alluding to Dante alluding to a famous and semi-legendary Italian love affair. And the Bible, of course. Earlier in the same poem, Keats throws in a lot of references to Greek myth too.