The scholars of the 11th and 12th century legal schools in Italy, France and Germany are identified as glossators in a specific sense. They studied Roman law based on the Digesta, the Codex of Justinian, the Authenticum (an abridged Latin translation of selected constitutions of Justinian, promulgated in Greek after the enactment of the Codex and therefore called Novellae), and his law manual, the Institutiones Iustiniani, compiled together in the Corpus Iuris Civilis. (This title is itself only a sixteenth-century printers' invention.) Their work transformed the inherited ancient texts into a living tradition of medieval Roman law.
The glossators conducted detailed text studies that resulted in collections of explanations.
In the Greek language, γλῶσσα (glossa) means "tongue" or "language." Originally, the word was used to denote an explanation of an unfamiliar word, but its scope gradually expanded to the more general sense of "commentary". The glossators used to write in the margins of the old texts (glosa marginalis) or between the lines (glosa interlinearis - interlinear glosses). Later these were gathered into large collections, first copied as separate books, but also quickly written in the margins of the legal texts. The medieval copyists at Bologna developed a typical script to enhance the legibility of both the main text and the glosses. The typically Bolognese script is called the Littera Bononiensis.
In the older historiography of the medieval learned law, the view developed that after the standard gloss had become fixed a generation of so-called commentators
Most of the older glosses are accessible only in medieval manuscripts: modern editions of only a few manuscripts exist.
- Four Doctors of Bologna Bulgarus Martinus Gosia Jacobus de Boragine Hugo de Porta Ravennate
- Azo of Bologna
- Franciscus Accursius
- Joannes Bassianus
- Tancred of Bologna
- Bernard of Botone