Nautical astrology: a forgotten early modern tradition.

While the link between navigation and astronomy is quite evident and its history has been extensively explored, the prognosticatory element included in astronomical knowledge has been almost completely left out. In the early modern world, the science of the stars also included prognostication known today as astrology. Together with astronomical learning, navigation also included astrology as a means to predict the success of a journey. This connection, however, has never been adequately researched. This paper makes the first broad study of the tradition of astrology in navigation as well as its role in early modern globalization. It shows how astrological doctrine had its own tools for nautical prognostication. These could be used when dealing with the uncertainty of reaching the desired destination, to inquire about the condition of a loved one, or an important cargo. It was widely used, both in time and geographical context, by navigators and cosmographers for weather forecasting and elections for the start of a successful voyage.