Of late two dainties were before me plac'd
Sweet, holy, pure, sacred and innocent,
From the ninth sphere to me benignly sent
That Gods might know my own particular taste:
First the soft Bag-pipe mourn'd with zealous haste,
The Stranger next with head on bosom bent
Sigh'd; rueful again the piteous Bag-pipe went,
Again the Stranger sighings fresh did waste.
O Bag-pipe thou didst steal my heart away --
O Stranger thou didst re-assert thy sway --
Again thou Stranger gav'st me fresh alarm --
Alas! I could not choose. Ah! my poor heart
Mum chance art thou with both oblig'd to part.

John Keats

http://www.poemhunter.com/poem/on-hearing-the-bag-pipe-and-seeing/