"Heard melodies are sweet, but those unheard
Are sweeter; therefore, ye soft pipes, play on"
- Which John Keat's poem these lines are taken from?

Ode on a Grecian Urn
BY JOHN KEATS

II
Where wert thou, mighty Mother, when he lay,
When thy Son lay, pierc'd by the shaft which flies
In darkness? where was lorn Urania
When Adonais died? With veiled eyes,
'Mid listening Echoes, in her Paradise
She sate, while one, with soft enamour'd breath,
Rekindled all the fading melodies,
With which, like flowers that mock the corse beneath,
He had adorn'd and hid the coming bulk of Death.