Ptolemy (Claudius Ptolemaios) lived in Alexandria, Egypt, in the second century. Ptolemy’s technical work on astronomy, originally written in Greek, was titled Almagest (“The Greatest”) by its Arabic translators. Ptolemy’s Almagest represents the culmination of ancient Babylonian and Greek mathematical astronomy. It achieved an unparalleled degree of accuracy in quantitative predictions of the positions of the planets. Regiomontanus was the leading European astronomer of the 1400’s. This Epitome of the Almagest by Regiomontanus was the first printed edition of the Almagest. It represents state-of-the-art astronomy at the time when Copernicus was a young man. A magnificent full-page woodcut depicts Ptolemy and Regiomontanus seated beneath an armillary sphere representing the music of the spheres.