The line "Heard melodies are sweet, but those unheard are sweeter" speaks true to the saying "A picture is worth a thousand words". The figures on the urn, such as the lovers beneath the tree, tell the story more eloquently than words and they speak to all languages and cultures. .
As Keats belonged to the Romantic poets, he relied on beauty to feed his soul in the midst of a rapidly changing world. He seemed to find life inferior to art because it is not constant and unchanging and it is understandable that he would find stability appealing considering his brief and tumultuous life. This is one reason why quests have an enduring quality- they force you to challenge reality and confront issues possibly not dealt with in everyday life.
The themes of immortality and morality can be seen throughout "Ode on a Grecian Urn". The unchanging marble of the urn can be considered as immortal just as the tale displayed on the urn. However positive the poem may seem about eternity and immortality, there are also negative insinuations hidden behind the facade of contentment. A quest for the reader to understand is- what is the real nature of the urn? The responder understands that the poet sees "the happy lover", as well as the "object of desire", three boughs and the piper creating the music. The urn contains a scene ambiguous in meaning. The reader is left to answer the questions posed by Keats in the fourth stanza.
The enduring quality of this text is the mystery surrounding it and also the irony of its subject matter. In his short lifetime, Keats became apart of his poetry by becoming all of its characters in one aspect or another. He is the "unheard melody that is never really heard or appreciated in its lifetime". He is the tree that will never go bare, because he died in the spring season of this year. He is the bold lover that will never kiss yet will forever love. Many believe the poet and the urn to be one in the same.