In bidding the phantoms of this day-dream adieu, Keats avows that there are others yet haunting him, and while imagery drawn from the sculptures on Greek vases was still floating through his mind, he was able to rouse himself to a stronger effort and produce a true masterpiece in his famous _Ode on a Grecian Urn_. It is no single or actually existing specimen of Attic handicraft that he celebrates in this ode, but a composite conjured up instinctively in his mind out of several such known to him in reality or from engravings. During and after those hour-long silent reveries among the museum marbles of which Severn tells us, the creative spirit within him will have been busy almost unaware combining such images and re-combining them. Cricitism can plausibly analyse this creation into its several elements. In calling the scene a 'leaf-fringed legend' Keats will have remembered that the necks and shoulders of this kind of urn are regularly encircled by bands of leaf-pattern ornament. The idea of a sacrifice and a Bacchic dance being figured together in one frieze, a thing scarcely elsewhere to be found, will have come to him from the well known vase of Sosibios (so called from the name of the sculptor inscribed upon it), from the print of which in the _Musee Napoleon_ there actually exists a tracing by his hand.[16] But this is a serene and ceremonial composition: for the tumult and 'wild ecstasy' of his imagined frieze, the 'pipes and timbrels,' the 'mad pursuit,' he will have had store of visions ready in his mind, from the Bacchanal pictures of Poussin, no doubt also from Bacchic vases like that fine one in the Townley collection at the British Museum and the nearly allied Borghese vase: while for the --heifer lowing at the skies And all her silken flanks in garlands drest, as well as for the thought of the pious morn and the little town emptied of its folk that old deep impression received from Claude's 'Sacrifice to Apollo' will have been reinforced by others from works of sculpture easy to guess at: most of all, naturally, from the sacrificial processions in the Parthenon frieze. [Illustration: PL XI THE SOSIBIOS VASE PROFILE AND FRIEZE: FROM ENGRAVINGS IN THE MUSEE NAPOLEON]