Ode on a Grecian Urn

In the poem, the speaker ADDRESSES and QUESTIONS the urn (just as Blake's speakers address and question the animals in "The Lamb" and "The Tiger). What does he say to and about the urn? What does the urn represent for him?

The speaker addresses the urn as "still unravish'd bride of quietness", "foster-child of silence and slow-time", and "Sylvan historian", which all lead the reader to assume this urn is still, unmoving and continuing to be so. Though there is some controversy on the term "still" here, where it could be taken to mean "motionless" or "as yet", however this doesn't effect how still and motionless the urn itself is. Though "still unravish'd" might imply the urn has secrets yet to tell which would be perfectly appropriate as the speaker has yet to unravel his own tale of the urn.
He asks the urn of the stories it holds. The speaker then goes on to describe the urn's beautiful outside not as decoration, but like a frozen scene, a story of its own. "Fair youth, beneath the tree, thou canst leave//Thy songs, nor ever can those trees be bare" "Who are these coming to the sacrifice?" "O mysterious priest,//Lead'st thou that heifer lowing at the skies,//And all her silken flanks with garlands drest?" He's mentioning each details as though it is a true scene that will never change. The urn is seen as the perfect thing, it has all it needs and these people upon it will never age nor change. The speaker almost idolizes the beauty of the urn that will watch humankind age and fade.