Irnerius

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.

He was born in Bologna about 1050.

At the urging of Countess Matilda of Tuscany he began to devote himself to the study of jurisprudence, taking the Justinian code as a guide. After teaching jurisprudence for a short while in Rome he returned to Bologna, where he founded a new school of jurisprudence in 1084 or 1088, which would rival the law school of Ravenna.

Some jurisprudence had been taught at Bologna, before Irnerius founded his school, by Pepo and a few others, and a tradition of jurisprudence had developed at Pavia since the mid-ninth century. He introduced the custom of explaining the Roman law by means of glosses, which originally were meagre interlinear elucidations of the text. But since the glosses were often too extensive to be inserted between the lines of the text, he began to write them on the margin of the page, thus being the first to introduce the marginal glosses which afterwards came into general use.

After the death of Pope Paschal II, he defended the rights of Emperor Henry V in the papal election and upheld the legality of the election of the imperial antipope Gregory VIII. After 1116 he appears to have held some office under the emperor. He died, perhaps during the reign of the emperor Lothair II, but certainly before 1140.

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