Starting from the 12th century in northern France, at the cathedral school of Anselm of Laon, a project was initiated to provide a comprehensive commentary on all the biblical books: the so-called Glossa ordinaria. This enterprise, destined for enormous success, quickly became the foundation for the teaching of divinitas in universities. In addition to acquiring a central role in theological activity, the Glossa also influenced the understanding of the Bible throughout Christendom, synthesising and preserving the great exegetical tradition of the past (primarily the Church Fathers and Carolingian exegetes, while not neglecting more recent contributions, sometimes anonymous). This volume reconstructs, for the first time, the tradition of a commentary on the Apocalypse wrongly attributed to Anselm of Laon, and publishes the critical edition of its two versions (the princeps for the older version, transmitted in the form of glosses), which represent an embryonic phase of the Glossa ordinaria on the Apocalypse, if not its preparatory materials linked to teaching. The intricate history of the Glossa, still far from being fully clarified in all its aspects, can thus be enriched with a new and significant piece, shedding light on the paths that led to its creation.