Despite being recognized as one of the most renowned masters of ars dictaminis of the late thirteenth and early fourteenth centuries, the figure of Laurentius de Aquilegia has not received the attention that the importance of his work requires. Of his varied production as a master of dictamen , it has been his synoptic treatises that have aroused the most interest among scholars, to the point that his two great summae have lacked monographic studies so far. This essay focuses on one of them, the Summa dictaminis composita iuxta doctrinam Tullii . It proposes an update of the state of the question, provides new evidence on the manuscript tradition and analyzes its most relevant doctrinal aspects. This approach to the author’s work should serve as a first step to a future critical edition of the Summa .