‘The Sunne and Moone of Knowledge’? Mathematical Astrology in Rollo, Duke of Normandy

This essay considers a short but fascinating scene in a neglected seventeenth-century play: Rollo, Duke of Normandy. The exact date and authorship of the play have been the subject of inconclusive debate, but the scholarly consensus is that a number of dramatists had a hand in it, including certainly John Fletcher and Philip Massinger, and possibly also Ben Jonson, Nathan Field, and George Chapman. The complex authorial make-up of the text helps to explain why the scene in question seems out of place in what is otherwise a play about political power and sibling rivalry. It equally makes the scene all the more curious as a carefully designed piece of drama relating to a very specific set of concerns about the status of astrological practitioners and their endeavours. I argue here that the astrologer scene in Rollo taps brilliantly into early modern concerns regarding the increasingly elitist nature of scientific knowledge, and the door this opened to deception and trickery. In the age of early modern drama, the thresholds between genuine technical expertise and disingenuous bluffing were the subject of confusion and anxiety. Rollo shows how both modes of behaviour might coincide in the same persons.