Vergil was the first to begin the dissociation of pastoral from the conditions of actual life, and just as his shepherds cease to present the features and characters of the homely keepers of the flock, so his landscape becomes imaginary and undefined.  This peculiarity has been noticed by Professor Herford in some very suggestive remarks prefixed to his edition of the Shepherd’s Calender.  ’The profiles of the Sicilian uplands,’ he writes, ’waver uncertainly amid traits drawn from the Mantuan plain.  In this confusion lay, perhaps, the germ of those debates between highland and lowland shepherds which reverberate through the later pastoral, and are still loud in Spenser.’  The gulf that separated Vergil from his predecessor, in so far as their treatment of shepherd-life is concerned, may be measured by the manner in which they respectively deal with the supernatural.  In the Greek Idyls we find the simple faith or superstition as it lived among the shepherd-folk; no Pan appears to sow dismay in the breasts of the maidens, nor do we find aught of the mystical worship that later gathered round him in the imaginary Arcadia.  He is mentioned only as the rugged patron of herds and song, the wild indweller of the savage woods as he appeared to the minds of the simple swains, who hushed their midday piping fearful lest they should disturb the sleep of the god.  It is true that Theocritus introduces mythological characters in the tale of Galatea, but it should be noticed that this merely forms the theme of a song or the subject of a poetical epistle to a friend.  Moreover, it is open to more than one rationalistic interpretation.  Symonds treats it as an allegory in harmony with the mythopoeic genius of Greek poetry.  It is equally possible to regard the Cyclops as emblematic merely of the rough neatherd flouted by the more delicate shepherd-maiden—­the contrast is of constant occurrence in later works—­for, alike in one of his own fragments and in Moschus’ lament, Bion is represented as courting this same Galatea after she has rid herself of the suit of Polyphemus.  Vergil was content with no such simple mythology as this.  He must needs shake Silenus from a drunken sleep and bid him tell of Chaos and old Time, of the infancy of the world and the birth of the gods.  This mixture of obsolescent theology and Epicurean philosophy probably possessed little reality for Vergil himself, and would have conveyed no meaning whatever to the Sicilian shepherds.  Its introduction stamps his eclogues with that unreality which has been the reproach of the pastoral from his day to ours.  The didactic homily was one fresh convention introduced.  Far more important was the tendency to make every form subserve some ulterior purpose of allegory and panegyric.[15] For the Roman its own beauty was no sufficient end of art.  That the Aeneid was written for the glorification of Rome cannot be made a reproach to the poet; the greatness of the end lent dignity to the means.  That the pastoral