This essay argues that the Christianized popular astrology of the early modern English printed almanac provided Shakespeare a powerful intellectual construct through which to explore the relationship between nature, man, and the divine in King Lear. Though Edmund’s depiction of astrology as superstitious and deterministic has often been critically accepted, in fact, Ptolemaic judicial astrology—the area of this vast and complex field engaged in King Lear—was a learned science that viewed individual fortune as contingent, a word with a specific astrological meaning that articulated the complex relationship between God’s providential plan and the free, individual Christian will. The essay situates the play’s references to astrology in the context of its popular practice in the early seventeenth century, and of long-standing debates about the art that bubbled up in the years just before Shakespeare wrote King Lear, in John Chamber’s A Treatise Against Judicial Astrology (London, 1601), and the response by Sir Christopher Heydon, A Defence of Judicial Astrology (London, 1603). It argues that astrology is a Trojan horse that smuggles into the play a providential narrative, one appropriate to the play’s pagan setting but which, by Shakespeare’s time, had long been infused with Christian principles. In this sense astrology provides a cosmological basis for understanding King Lear’s complex exploration of providence and the origins of evil, one that is grounded in the humble but ubiquitous early modern almanac.