The study of medieval preaching – and its main source, the sermon – offers a privileged insight into intellectual work and its techniques. This vast system of mass communication of the Church’s message and its values left a wealth of written traces, bearing witness to the ordinary, daily preaching that was offered throughout all of Christendom. Through this source, we can approach the persuasion strategies and also the tools used by the preachers in their intellectual work. Among those tools was the distinctio. This technique, extremely widespread in the Middle Ages from the late 12th c. onwards, consisted of considering a word according to its various senses, properties or characteristics, and supporting them with biblical citations. Distinctiones were a key ingredient of sermons from the early 13th c. onwards, just like exempla (short narratives used for persuasion), but contrary to the latter, distinctiones have never been studied in depth or even surveyed properly. The aim of the DISTINGUO project is to bridge this gap, first by developing a knowledge base and finding aid on medieval distinctiones in the context of preaching, laying the necessary foundation for a new field of study, and then by implementing a research programme exploring the use of distinctiones, their circulation, their link with exegesis, their mnemotechnic utilization, etc.