Arialdus deacon and martyr of the church of Milan in the 11th century. The Roman Church in the north of Italy was then very corrupt; a wide-spread licentiousness, originating from the unnatural institution of priestly celibacy, prevailed. Great numbers of the clergy kept concubines openly. Some earnest men, shocked by this flagrant evil, vainly imagined the strict enforcement of celibacy the only effectual cure. Chief among these reformers stood Arialdus, whose life was one continued scene of violent controversy. Although successively sanctioned by Popes Stephen X, Nicholas II, and Alexander II, he found little sympathy among his brethren, and used to complain that he could only get laymen to assist him in his agitation. Having at length succeeded in obtaining a papal bull of excommunication against the archbishop of Milan, a fierce tumult ensued in the city, whose inhabitants declared against Arialdus and his coadjutors. Arialdus now fled to the country; but his hiding-place being betrayed, he was conveyed captive to a desert isle in Lake Maggiore, where he was murdered by the emissaries of the archbishop, and his remains thrown into the lake, June 28, 1066. He was afterward canonized by Pope Alexander 2. — Acta Sanctorum, June 28.