The Confluence of Religious Cultures in Medieval Historiography comprises the first interdisciplinary study of the General e grand estoria (GE), a history of the world written in Old Spanish. The GE is Medieval Europe’s largest universal history, and one of the only such histories written in the vernacular. It brings together Christian, Jewish, Islamic, and apocryphal interpretations of the Bible, alongside the mythological and historiographical traditions of the classical Greek and Latin world as well as French and Arabic sources. Unfortunately, and perhaps due to its length and complexity, the GE remains little known in its entirety. Working together since 2016 with the support of the SSHRC, our international, multidisciplinary research team has successfully tackled the challenges that in the past have prevented scholars from achieving a full comprehension of, and an efficient way of presenting to the public, this complex and voluminous work.