[Sidenote: Manilius.] A poem on astronomy and astrology (_Astronomica_), ascribed in some of the manuscripts to an otherwise unknown Marcus or Gaius Manilius, is a didactic poem of unusual merit. As preserved it consists of five books, the last of which is incomplete. If, as is probable, a sixth book once existed, the whole work contained about five thousand lines. Even in its present condition it is the longest didactic Latin poem except the _De Rerum Natura_ of Lucretius. The poem is, as a whole, rather uninteresting, but contains passages of great vigor, showing independence of thought and remarkable power of expression. The author has an easy mastery of hexameter verse, in which he is superior to Lucretius; but with all his skill in versification, his earnestness, his learning, and his originality, he can not entirely overcome the prosaic nature of his subject. The poem is uneven, at times prosaic, sometimes rhetorical, not often, if ever, rising to lofty heights of poetic fancy, but serious and thoughtful. A large part of it is occupied with astrology, and other portions describe the heavenly bodies. In the introductions to the several books, and in digressions, theories concerning the origin of the world, the nature of man, and the power of fate are introduced, showing that the author accepts in the main the Stoic doctrines as opposed to the Epicurean teachings of Lucretius. So he maintains that the world is not the product of blind forces but of a divine will: Who can believe that masses of such size Were formed from particles without God’s aid, And that the world did blindly come to pass? If mere Chance gave it us, let mere Chance rule. But why do we perceive in stated turn The constellations rise and, as it were By order giv’n, run through their course prescribed, Nor any hastening leave the rest behind? Why do the selfsame stars adorn the nights Of summer ever, and the selfsame stars The winter nights? And why does every day Return the world its form and leave it fixed?[76] Various mythological tales are inserted with a view to enlivening the poem, but the author lacks narrative skill. The most elaborate of these episodes, in which the story of Perseus and Andromeda is told,[77] shows, however, good descriptive ability and lively rhetoric. Manilius is not a great poet, but he treats, not without success, a subject new to Roman poetry, and shows himself to be a man of original power of mind and of serious purpose. With all its defects, the _Astronomica_ has also great merits.