This chapter will consider astrological prognostications of the comets of 1618 from English sources, particularly John Bainbridge’s An Astronomicall Description of the Late Comet, written in 1618, and England’s Prophetical Merline, written by William Lilly in 1642/3 in the opening days of the English civil war and the concluding stages of the Thirty Years war. Bainbridge’s text was written at a time of peace, while Lilly’s text looked back to the comet as an omen of war and related it to the Jupiter–Saturn conjunction of 1603. The text was published at a time when censorship in England was breaking down as the central government collapsed, an event which precipitated a boom in astrology. This chapter explores Bainbridge and Lilly’s texts as test cases of how cometary significance and/or effects were viewed in the early seventeenth-century, after the invention of the telescope but before the decline of astrology’s intellectual credibility at the end of the century.