 Renaissance humanism did not necessarily promote natural philosophy, but its emphasis on mastery of classical languages and texts had the side effect of promoting the sciences. Georg Peurbach (1423–1461) and (Johannes Müller) Regiomontanus (1436–1476) studied Greek for the purpose of producing an outline of Ptolemaic astronomy. By the time Regiomontanus finished the work in 1463, it was an important commentary on the Almagest as well, pointing out, for example, that Ptolemy’s lunar theory did not accord with observations. He noted that Ptolemy showed the moon to be at various times twice as far from the earth as at other times, which should make the moon appear twice as big. At the time, moreover, there was active debate over Ptolemy’s deviations from Aristotle’s requirement of uniform circular motion.