BALDUS DE UBALDIS, PETRUS Italian jurist of the noble family of the Ubaldi, studied civil law at Perugia under Bartolus, gaining the doctorate at the age of 17. Federicus Petrucius of Siena was his master in the canon law. Upon his promotion to the doctorate he went to Bologna, where he taught for three years; and then became a professor at Perugia, where he stayed 33 years. Afterwards he taught at Pisa, Florence, Padua and Pavia, when the schools of law in those universities disputed the palm with Bologna. The extant Treatises of Baldus hardly account for the reputation which he had in his own day, due partly to his public career, and partly to the fame of his consultations, of which there are five volumes (Frankfurt, 1589). Baldus was the master of Pierre Roger de Beaufort (Pope Gregory XI.), whose successor, Urban VI., called Baldus to Rome to assist him in 1380 against the anti-pope Clement VII. Cardinal de Zabarella and Paulus Castrensis were his pupils. His Commentary on the Liber Feudorum is one of his best works, most of which he left un finished. His brothers Angelus (1328-1407) and Petrus 1400) were also eminent as jurists.