In fact, I can give a much better example. I've just written a waltz-time, countryish melody to John Keats' poem "Fill for me a brimming bowl". (If you google the words to that poem you'll see that it's a great poem to set to music: it scans and rhymes really organically and isn't remotely fussy.)

The poems of John Keats are out of copyright for obvious reasons. Strictly speaking a book publisher could claim I was using the version printed in their book, but as it is a poem printed in several different books by several different publishers, they couldn't enforce that: even more so as I tweak the odd archaism for the sake of meter.

Could I not copyright a recording of that as "John Keats/Matthew Milton"? I can't think of any reason why not.