Reformer, and martyr; b. Cantu, Italy, c. 1000; d. on an island in Lake Maggiore, Italy, June 27, 1066. Although he had never been elevated beyond the rank of deacon, he was chosen by Henry III to lead the reform of the Milanese clergy, a movement assisted by the Milanese Cardinal Anselm II of Lucca and the noted clerical historian Landulph Cotta (fl. 1085). Reform was already a leading demand of the patarines, but Guido of Velate (d. 1071), archbishop of Milan, led the forces that opposed it. Soon after Arialdo began preaching at Varese, a provincial synod with Guido presiding excommunicated Arialdo and Landulph, both of whom appealed to Rome. Thereupon the Roman legates, Anselm of Baggio and Hildebrand, who became popes as alexander ii and gregory vii respectively, reached Milan and encouraged the reformers to persevere. When Landulph died, his brother erlembald led the cause, associating his name and sanctity with Arialdo, whose feast he shares. A bull of excommunication against Guido prompted his associates to capture Arialdo and isolate him on an island in Lake Maggiore. There he was assassinated by two priests; his body was later brought to Milan by Erlembald. In 1068 Alexander II declared Arialdo a martyr, and his ancient cult was confirmed by Pius X in 1904.
Feast: June 27.
Bibliography: Acta Sanctorum June 7:250–272. c. pellegrini, I santi Arialdo ed Erlembaldo (Milan 1897). c. castiglioni, I santi Arialdo ed Erlembaldo e la Patarìa (Milan 1944).
[n. m. riehle]