sentences:  Here he became, successively, doctor and professor of canon law and also obtained an ecclesiastical benefice as canon.Gerhard, Bishop of Parma (d. 1301) attached Guido to himself; and remained his patron also as Cardinal-Archbishop of Sabina.To this patron Baysio dedicated his chief work, a commentary on the "Decretum" of Gratian, which he wrote about the year 1300 and entitled "Rosarium Decretorum".