The Writing on the Wall

I still haven't solved the mystery of who wrote three lines of Keats's Lines on the Mermaid Tavern on the wall during our housewarming party in September. There were too many people in attendance to really figure it out, but I eliminated all of my friends — even though they would be the likely suspects, with half of them being literature graduate students. If anyone has any insight, tell me. But before you all rush to claim authorship, whoever wrote it left out the third line of the stanza, which both opens and closes the poem.

Souls of Poets dead and gone,
What Elysium have ye known,
Happy field or mossy cavern,
Choicer than the Mermaid Tavern?