"Beauty is truth, truth beauty" This famous quote is taken from-

'Beauty is truth, truth beauty,—that is all
Ye know on earth, and all ye need to know.'
- Ode on a Grecian Urn(1820); John Keats

Other Quotation of John Keats:
- Beauty is truth, truth beauty.
- A thing of beauty is a joy forever.
- Heard melodies are sweet but those unheard are sweeter.

Source: The Oxford Dictionary of Quotation.