imagined corners

We sang Lee Hoiby's arrangement of John Donne's At the Round Earth's Imagined Corners on Sunday.

Someone pointed out that when Donne wrote his poem, the idea that the earth was round had not been around that long in popular culture.

I read the text repeatedly, and while I have some understanding of what he was writing, it is the imagery that continues to burn through in my mind.

I know I've heard at least one other arrangement of the text, but cannot put my finger on what it was or when I heard it.