Astronomy and astrology cannot be separated in the Middle Ages and the early modern period as they are today. For the educated medieval man or woman both the movement of the heavenly bodies and their effect on man were entirely natural and subject to scientific study and prediction. It was possible for learned men to argue about how the influence of the planets was transmitted, about whether astrologers were performing their profession competently, or only telling their employers what they wanted to hear, and even whether it was lawful to use information about the movement of the stars and planets to foretell the future or to excuse a person's behavior. But all of these arguments took as their basis a shared belief in the influence of the planets on earth in general, and on man in particular.