Corpus Juris Civilis
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.