Ambrosius Theodosius Macrobius was a high-ranking official of the later Roman Empire, quite possibly a pagan, whose three surviving works are the Saturnalia, which describes a symposium set in 384 C.E.; a treatise comparing Greek and Latin verbs, and the Commentary composed in the early fifth century on Cicero’s Dream of Scipio. This last work was an important source of Neoplatonic cosmology and philosophy in the Middle Ages. It expounds the last chapter of Cicero’s Republic, in which Scipio the Younger is taken in a dream by his adoptive grandfather up to the stars to look back on the Earth and to contemplate the heavenly destiny of those who serve the state. Macrobius ranged widely over scientific topics in his Commentary: the nature of number and its presence in the cosmos and human life, astronomy, geography, and the harmony of the spheres. He wrote at a fairly basic level, not always accurately, and provided some illustrative diagrams of the spheres, rainfall, and celestial and terrestrial zones. Despite not fitting neatly into the categories of the *quadrivium, his work became a useful medieval school text, surviving in more than two hundred manuscripts, of which nearly half were copied in the twelfth century.