This article explores John Aubrey's (1627–1697) extensive use of astrology in his biographical collection
Brief Lives
(1680–1681), which has been widely celebrated for its vivid portrayal of seventeenth-century English culture and society. Aubrey's life writing was not only informed by his antiquarian pursuits, the vibrant coffee house culture of his time and his lively scientific community, but also by the practice of astrology. Through Aubrey's horoscope collection,
Collectio geniturarum
(1674–1690), and his correspondence with a wide astrological network, this article traces his deep engagement with the practice. In squarely focusing on these two sources, I argue that Aubrey greatly relied on astrological methods to inform his life writing. In making his collection of horoscopes, Aubrey drew on a long tradition of astrological data gathering. Aubrey's careful collation and calculation of data to verify birth times, identify major life events and determine ‘ingenious’ traits also contributed to a wider effort to reform astrology considering the nascent experimental philosophy. By examining Aubrey's multifaceted astrological writings, this article clarifies one of Aubrey's key techniques used in his early sketches of
Brief Lives
. More broadly, it further complicates the historical narrative that astrology was largely marginalized in late seventeenth-century English intellectual and scientific communities.