During the first 30 years of the 14th century, in the Umbrian convent of Gualdo Tadino, a Franciscan (Paolo da Gualdo, also called Anonimo of Gualdo) compiled four historical and hagiographie texts. Two of these are noted in the original, two others are reconstructable based on copies made between the 15th and 17th centuries. The tradition surrounding fra Paolo was elaborated by four 17th century Umbrian scholars, the same individuals who made the copies of the two lost texts. This tradition and the copies of the two lost texts received ample attention from local erudition of the 19th and 20th centuries. From an analysis of all that happened concerning these manuscripts (the originals and the copies) of Gualdo's medieval memorialist texts, it is possible to demonstrate that: a) fra Paolo existed but was not the author of the corpus; 2) a 14th century compiler of other chronicles, fra Elemosina, was the author of all the manuscripts; 3) the most important of the texts attributed by the tradition to fra Paolo - the Chronicle of Gualdo - was the result of the interpolation carried out in the 16th century, by the forger Alfonso Ceccarelli, who used authentic medieval material. The interpolation, from which descends the whole manuscript tradition of the text of the Chronicle, was realized with the complicity of the local nobility who were engaged, in the 16th century, in the defense of the territorial jurisdiction of their homeland.