The corpus of the so-called Revelationes of Peter Infant of Aragon (1305-1381), preserved in the Apostolic Archives of the Vatican (Arm. 54, De schismate vol. 17, ff. 122r-152r), represents a diverse and multilingual collection of texts related to the figure of Peter of Aragon and written between 1365 and 1381 in the context of the disputes over the return of the Pope to Rome and the Great Schism of 1378. Not all of these texts, however, were written by Peter himself: while Peter consistently refers to a quaternus containing his revelations, the extant corpus contains, along with the texts of Peter, the examination of these texts by a theological commission, as well as sermons, prophesies and letters in Latin, Catalan and Castilian, thus illustrating the wide geographical and cultural scope of this collection. This study aims to reconstruct the content of Peter's original quaternus by separating his original writings from those later attributed to him. By analysing these layers, the quaternus of Peter of Aragon serves as a case study for understanding medieval concepts of authorship, textual authority and the interplay between individual identity and collective memory in manuscript traditions.