A diagram that places two planets in orbit around the sun was inserted into the textual space of a Timaeus manuscript of the late 11th century as well as three more in the 12th century. The diagram derives from a Carolingian tradition of study of Martianus Capella’s astronomy and shows his continued authority into the twelfth century. By way of Capella and through similarly-inspired commentaries on Macrobius’ Commentary on the Dream of Scipio, the idea of circumsolar motion for Mercury and (...) Venus became a well-known and authoritative theme for William of Conches and other scholars in the eleventh and twelfth centuries wo interpreted Plato in terms of current scientific knowledge. (shrink)