Bulgarus

He was the most celebrated of the famous Four Doctors of the law school of the University of Bologna and was regarded as the Chrysostom of the Glossators, being frequently designated by the title of the "Golden Mouth" (os aureum).

[1][vague] According to popular tradition, all four of the famous Four Doctors (Bulgarus, Martinus Gosia, Hugo de Porta Ravennate and Jacobus de Boragine) were pupils of Irnerius; however, while there is currently no insuperable difficulty in substantiating this claim with regard to Bulgarus, Friedrich Carl von Savigny considered the evidence to be insufficient to support this claim.

Joannes Bassianus, Azo and Accursius all numbered amongst its notable adherents, each of whom, in turn, went on to exercise a commanding influence over the course of legal studies in Bologna.

However, this commentary has since been properly credited to its true author, Cujacius, based on internal evidence contained in the additions annexed to it, which were undoubtedly penned by Placentinus himself.

According to Savigny, it is a model specimen of the excellence of the method introduced by Irnerius, and a striking example of the brilliant results obtained in a short period of time by virtue of a constant, exclusive study of the sources of law.