Historically, the Timaeus was one of the most influential of all the dialogues of Plato. If you have heard of the lost continent of Atlantis, you are aware of one of its legacies, since the Timaeus is the original source of the Atlantis myth. The dialogue is also where Plato discusses his idea that the five Platonic solids (cube, tetrahedron, octahedron, icosahedron, and the dodecahedron) relate to ancient idea of the elements (earth, fire, air, water, and the famous “fifth element”). But even more important, the Timaeus includes a cosmic creation myth that spells out Plato’s understanding of the universe and its purpose. This cosmogeny inspired Gnostics and orthodox Christians alike. Translated into Latin by Cicero, the Timaeus was the only dialogue of Plato available to thinkers in the Latin West in Late Antiquity and the Early Middle Ages, increasing its importance and influence. John Hamer of Toronto Centre Place will outline the contents of the Timaeus, will look at its influence on ancient and Medieval thinkers, as well as why its importance among Plato’s works has subsequently waned.