Volume 3 no 2

An Astrological Prognostication to Duke Cosimo de' Medici of Florence  

Claudia Rousseau.

Abstract.

The Italian High Renaissance saw the high point of the use of astrology in the timing of both military and political events. It is known that Cosimo I de' Medici, Duke of Florence, delayed the decisive battle in his war against Siena in 1554, against the advice of his commanders in the field. A previously unpublished astrological prognostic may have influenced his military strategy which, in fact, led to his eventual victory at Marciano on 2 August 1554. This paper presents a discussion of the circumstances surrounding the campaign, and a translation and analysis of the prognostic sent to Duke Cosimo in March 1554 by the astrologer Francesco Formiconi.