ONE OF THE IMPORTANT ROLES of epic was its didactic function, including teaching about the gods (and then God), imparting ethical ideals, and conveying knowledge of the natural universe. A key figure in the evolution of the epic into a sort of encyclopedic text was Vergil, both as he conceived his own task in relation to Homer1 and as he was later elevated, first to the status of hermetic philosopher and then in the medieval period to that of a necromancer. By the time Dante came to write the Divine Comedy, one of the basic requirements for the epic poem was that it should be a comprehensive guide to all human knowledge. It should be a microcosm, whose carefully constructed designs and patterns would provide an orderly map of the universe, one that would also be elegant, communicating the whole of knowledge in an aesthetically satisfying form. Nor were the rules simply left unstated. The classic digest of the requirements was made by Tasso in his Discourses on the Heroic Poem, where he outlined what the epic poet would need to know in order to be successful. It was a daunting prospect, since the poet essentially had to have encyclopedic mastery, demonstrated in the architecture of the text itself: