One had a lovely face,
And two or three had charm,
But charm and face were in vain.
Because the mountain grass
Cannot keep the form
Where the mountain hare has lain.
Not only every great poet, but every genuine, but lesser poet, fulfils once for all some possibility of language, and so leaves one possibility less for his successors.
What a poem means is as much what it means to others as what it means to the author; and indeed, in the course of time a poet may become merely reader in respect to his own works, forgetting his original meaning.