In his Life of Filippo Maria Visconti, written around 1447, Pier Candido Decembrio recounted how Gian Galeazzo Visconti, the first duke of Milan, became convinced that his younger son Filippo Maria would make a better leader of his territories than his elder brother Giovanni Maria. Gian Galeazzo’s preference for his younger over his older son was based not just on his personal knowledge of his sons’ characters but, even more importantly, on the opinion of his court astrologers, who asserted that Filippo Maria would bring glory to the family name. If Filippo’s rule over Milan was written in the stars, it was, as Monica Azzolini’s finely crafted book demonstrates, only one of many instances in which court astrologers played key roles in Renaissance Italian politics.
Burckhardt famously argued that the despotism of the dukes of Milan “shows the genuine Italian character of the fifteenth century”—by which he meant ruthless, calculating, and pragmatic rulers of states “depending for existence on themselves alone, and scientifically organized with a view to this object.” Such despots, who mastered the politics of “the state as a work of art,” were supposedly confident that they held their destiny in their own hands.1 In light of Burckhardt’s characterization of these Italian Renaissance princes—a view endorsed by subsequent political historians—it is jarring to discover that the ducal court in Milan was a major site of astrological patronage. Astrologers, such as Ludovico Maria Sforza’s court astrologer Ambrogio da Rosate Varesi, could amass a huge fortune and wield extraordinary influence, rising to spectacular heights in their respective courts.
The dukes of Milan used astrology for a host of different purposes. Astrologers determined the most propitious times to administer medicine, to marry and lie with one’s bride, to travel, and to wage war. They even cast nativities and horoscopes to predict when an enemy would die. For almost every significant decision, whether personal, political, military, or diplomatic, the dukes of Milan consulted their astrologers and sought their prognostications.
But did they actually believe in astrology? Azzolini ponders this question on a number of occasions in her book, and her answers are uniformly balanced and revealing. The matter of belief, Azzolini observes, is reductive in the case of astrology and, in the final analysis, impossible to assess. As a pragmatic science, astrology competed with other sciences in what she calls the early modern “predictive market” (66). The dukes of Milan were not blind believers in astrology; they were avid consumers [End Page 389] of astrology. The “science” of astrology was one among many forms of expertise that gave rulers a sense of control over an uncertain future. As Ash pointed out, the notion of expertise was in flux during the early modern period. Traditional practitioners might know how to do things, but early modern experts could claim even more—to know how and why things worked,2 The dukes resorted to their advice, as they did to that of other counselors, in spite of often imperfect results. Although Azzolini does not press the point, the court astrologers could well have been the victims of their own success. As princes demanded increasingly precise predictions for particular events, astrologers faced the dilemma of honoring their patrons’ requests while risking predictions that fell short of the mark.
Previous histories of astrology tended to concentrate on the intellectual and scientific foundations of the art, ignoring astrology’s application in everyday life. Political historians have traditionally considered astrology to be a mere superstition, largely ignoring it. Azzolini’s book provides a needed corrective to both tendencies. Utilizing a vast range of archival and published sources, Azzolini ventures deep into the culture of the Renaissance court. Weaving together the methods and interests of the history of science and of Renaissance political and cultural history, Azzolini has produced a sophisticated, interdisciplinary analysis of a science and a profession that played a key role in the political life of the Renaissance, challenging current assumptions about Renaissance politics and making important contributions both to...