I wonder why the names for planets with medieval origins were chosen instead of the traditional Roman ones. Didn't Lewis also have a fondness for Greek and Roman mythology? How about Aphrodite for Venus, Hermes for Mercury, Ares for Mars. I don't think the names Malacandra, Perelandra, and Thulcandra were very familiar to modern readers-- couldn't they identify more easily with the Greek and Roman names that we use today than with what the inhabitants called these worlds? Unless, perhaps Lewis thought that the strange terminology would give the stories a more exterrestrial quality. However, the names had apparently had a connection to medieval Earth.
Larry W.