Which 1819 poem by John Keats concludes with the philosophical assertion, "Beauty is truth, truth beauty,—that is all / Ye know on earth, and all ye need to know"?

Ode on a Grecian Urn

This work is one of Keats's famous five odes and examines the relationship between the fleeting nature of human life and the permanence of art. The speaker addresses an ancient ceramic vessel decorated with scenes of pastoral life and frozen moments.