Wikipedia
Huguccio was an Italian canon lawyer (d. 1210).
He studied at Bologna, probably under Gandolphus, and taught canon law in the same city, perhaps in the school connected with the monastery of SS. Nabore e Felice. He is believed to have become Bishop of Ferrara in 1190.
Among his supposed pupils was Lotario de' Conti, afterward pope Innocent III, who held him in high esteem as is shown by the important cases which the pontiff submitted to him, traces of which still remain in the " Corpus Juris" (c. Coram, 34, X, I, 29). Two letters addressed by Innocent III to Huguccio were inserted in the Decretals of Gregory IX (c. Quanto, 7, X, IV, 19; c. In quadam, 8, X,III,41). However, Innocent probably was not well acquainted with Huguccio's ideas on the Eucharist when he issued the decretal Cum Marthae (X 3.41.16).1
He wrote a "Summa" on the " Decretum" of Gratian, concluded according to some in 1187, according to others after 1190, the most extensive and perhaps the most authoritative commentary of that time. He omits, however, in the commentary the second part of the Causae of the Decretum of Gratian, Causae xxiii-xxvi, a gap which was filled by Johannes de Deo.
Huguccio argued, in a widely known opinion, that a pope who fell into heresy automatically lost his see, without the necessity of a formal judgment.