Four Doctors of Bologna

The Four Doctors of Bologna (Latin: Quatuor Doctores) were Italian jurists and glossators of the 12th century, based in the University of Bologna: Bulgarus, Martinus Gosia, Jacobus de Boragine and Hugo de Porta Ravennate.

[1] Their teachings in the law school of Bologna were based on glosses and commentaries on the rediscovered Corpus juris civilis of Justinian.

[2] The revived importance of Roman law, in the form of medieval Roman law, embodied by the Quattuor Doctores made its first impact in the political arena in 1158, when they gave their support to Frederick Barbarossa's Diet of Roncaglia in his conflict with the Italian communes over imperial rights in Lombardy.

Bulgarus took the law at face value and applied the narrowest interpretation, the ius strictum; Martinus, on the other hand, applied the legal principle of aequitas, "equity" or "equivalence", which permitted broad latitude in extending Roman principles to modern situations.

[3] In the 13th century the combined tradition of the doctores bononienses were summarized in the form of a glossa ordinaria of Roman law, compiled by Accursius.