BISHOP OF VERCELLI, Hatto. - Few reliable facts are known about his life. Of a noble Lombard family, we know that in 924 he was elected bishop of Vercelli, a diocese he governed for a long time. He had many dealings with the rulers of the time, Berengar II, Hugh and Lothair II, from whom he received privileges and donations for his own Church: it is not certain, however, that he was archchancellor of this last king. Despite these relations and his principles of obedience to authority, because it is established by God (see for this the letter to Valdone, bishop of Como, where a dependence on the Carolingian writers of the 9th century is evident), A. opposed with great courage Berengar II, who did not respect the freedom of the Church.
His literary activity is remarkable: we have from him a long Expositio in epistulas Pauli, certainly authentic, numerous letters (some of them interesting for their prose rhythm) and pastoral sermons; the authenticity of the Polyptychum, a summary of moral philosophy, which contains interesting polemical passages against the Germans and Burgundians who were in Italy, is disputed. A. is even more important in the history of the Church of the 10th century for his work of great pastoral zeal in reforming and improving the clergy and the religious life of his diocese. A document of this reforming activity is his Capitolare, that is, a collection of one hundred canons, which concern the duties of ecclesiastics, the administration of the sacraments, the observance of the liturgy, etc.; they are all ancient conciliar provisions that are repeated: much insistence is placed against the rampant Nicolaitism and simony, which A. is the first to call heresy. In the Libellus de pressuris ecclesiasticis, a true canonistic treatise in three books, written between 940 and 943, A. combats the abuse of deferring ecclesiastics to lay tribunals, the sacred ordination given to unworthy or incapable persons, the squandering of the goods of the Church done by laymen.
We do not know the date of A.'s death, which, however, certainly occurred before 964, the year in which the successor Ingone is already bishop of Vercelli.
Bibliography
Mai, in PL 134. The Polyptychum has a modern edition (with introduction and German translation) by G. Goetz, who denies the attribution to A. (Abhandl. d. phil. hist. Klasse d. sächs. Abad. d. Wim., XXXVII, II, Leipzig 1922). On A. have written: I. Schultz, Atto von Vercelli, Göttingen 1885; E. Pasteris, A. di V. ossia il più grande vescovo e scrittore italiano del sec. X. Vita, opere, prose ritmiche, Milan 1925; P. Pirri, A. di V., in La Civiltà Cattolica, 1927, I, pp. 27-42. For other information see also F. Savio, Gli antichi vescovi d'Italia: Il Piemonte, Turin 1898, p. 451 ff.; M. Manitius, Gesch. der lat. Liter. des Mittelalters, II, Munich 1923, especially pp. 27-34; A. Fliche, La riforme gregorienne, I, Louvain-Paris 1924, pp. 61-74.
Michele Maccarrone