At the beginning of the XIV century the school of commentators replaces that of glossators.
In previous centuries, the glossators had approached the Justinian texts without finding any formal or substantial differences between the Roman sources and the free interpretation derived from them; commentators, instead, developed a more detailed approach, no longer limited to exegetically glossing the sources, but seeking concrete answers to the problems of the time. They developed and exposed their theories, organically building a new law, more detached from the textual arrangement of the Corpus.
The first member of the new school is the literate Cino da Pistoia, the poet friend of Dante's, author of the Lectura super codice, and master of the most notable representative of the school, Bartolo da Sassoferrato, master, in turn, of Baldo degli Ubaldi, another prominent figure.
The object of the study still remains the Corpus, but the analysis follows a different methodology, derived from scholastic philosophy and adapted to the law: commentators identify the ratio behind the rules - that is, the guiding principle, and through the extension by analogy to unforeseen cases, create new institutions.
