Sixteenth-century astrology was considered by its practitioners to be allied to a wide range of disciplines, including medicine, the magical arts and the mathematical arts. The last of these associations was particularly important, since it formed a cornerstone of the legitimation of the celestial art. Astrologers in late Tudor England sought to show, therefore, that astrology shared the characteristics of the increasingly strong and well-defined domain of the mathematical arts, and that it was an important ally of many of the (...) individual arts, such as astronomy, navigation, and instrument-making. This association was demonstrated in practice, where astrology and other mathematical arts were mastered by the same practitioners. (shrink)