150), the Alexandrian astronomer whose works were the basis of all European astronomy throughout the Middle Ages and Renaissance, the planets were lights set into a series of transparent spheres turning around the Earth, which was the center of the one and only universe.Dante (1265–1321), in his Paradiso, describes the ascent of his narrator through the spheres of the Moon, the planets from Mercury to Saturn, and thence to the sphere of the fixed stars and the heavens of the angels.