Built between 1490 and 1492, the chapel of the humanist Giovanni Pontano is one of the most interesting and controversial cases of fifteenth-century Neapolitan architecture. The chapel has been attributed to different architects including Fra Giocondo, Francesco di Giorgio Martini, and Baccio Pontelli; however, none of these attributions can be considered conclusive. Pontano himself discourages us from trying to propose a new name in addition to those which have already been suggested, by repeatedly signing the pavement of the chapel with an unequivocal Pontanus fecit. This feature has never been remarked upon by historians, yet Pontano’s inscription should be seen as a true signature of the work and represents a central element for our understanding of the building and above all of Pontano’s relationship with the artistic culture of his time. Wishing to inform posterity about who was responsible for the chapel, he proposes himself as its only true auctor. This matches perfectly what the humanist would shortly afterwards express in his treatise De magnificentia, in which he describes the patron as the auctor of the work of art who through his knowledge of architecture and sculpture is thereby able to show the architect and sculptor the means how they might achieve magnificence in the artistic work which they are going to carry out on his behalf. Pontano’s use of such signatures reflects a precise humanistic interest in artists’ signatures which emerged at the end of the fifteenth century and which led to the resumption of this practice in antiquarian terms. While the graphic form of the inscription in capital letters and its arrangement within a scroll show a careful observation of ancient monuments, the wording of the sentence with the name in the nominative and the verb facere, employed in the perfect tense (fecit), reveals a precise ancient literary source. Pontano’s signature is an accurate quotation from Pliny’s preface to the first book of the Naturalis Historia. With his choice of the inscription Pontanus fecit, Pontano is consciously making a precise statement: he not only communicates his role as the author of the chapel, as well as its patron, but also expresses his conviction that he has perfected the work of art to his full satisfaction and does not have to fear the judgment of posterity.