"Forget the Past, his fate and fame shall be
An echo and a light unto eternity!"
- Which poem these lines are taken from?

Adonais: An Elegy on the Death of John Keats
BY PERCY BYSSHE SHELLEY
I weep for Adonais—he is dead!
Oh, weep for Adonais! though our tears
Thaw not the frost which binds so dear a head!
And thou, sad Hour, selected from all years
To mourn our loss, rouse thy obscure compeers,
And teach them thine own sorrow, say: "With me
Died Adonais; till the Future dares
Forget the Past, his fate and fame shall be
An echo and a light unto eternity!"