Irnerius

For the saint with this name, see Himerius of Cremona.

Irnerius (c. 1050 – after 1125), sometimes referred to as lucerna juris ("lantern of the law"), was an Italian jurist, and founder of the School of Glossators and thus of the tradition of Medieval Roman Law.

He taught the newly recovered Roman lawcode of Justinian I, the Corpus Juris Civilis, among the liberal arts at the University of Bologna, his native city. The recovery and revival of Roman law, taught first at Bologna in the 1070s, was a momentous event in European cultural history. Irnerius' interlinear glosses on the Corpus Juris Civilis stand at the beginnings of a European law that was written, systematic, comprehensive and rational, and based on Roman law.