Who was Gratian?

monk Gratian
Gratian was an Italian monk and founder of the science of canon law. He was probably a Camaldolite monk and was a teacher at the convent of St. Felix and Nabor in Bologna. About 1140 he compiled his scholarly work known as the Decretum Gratiani or Concordia Discordantium Canorum, a collection of the "Decretum," of canons, issued by the popes and councils up to that time. The work consists of three sections: the first is concerned with the sources and principies of ecclesiastical law and with religious persons; the second deals with canon law as it relates to property, marriage, and penance; the third is concerned with the use of liturgy and the sacraments. A revised version of the work forms a part of the Corpus Juris Canonici, a later and more complete compilation of canon law.