 Complete the following phrase:  Among the bishops of the following period, a certain number are especially prominent, either on account of the offices they filled in the Empire, or for their personal qualifications; thus Witgar, Chancellor and Archchaplain of Louis the German; Adalbero 887910, of the line of the Counts of Dillingen, confidant and friend of Emperor Arnulf, who entrusted Adalbero with the education of his son, the German King Louis the Child, distinguished for generosity to the monasteries. The See of Augsburg reached the period of its greatest splendor under Saint Ulrich 923-973. He sought to improve the low moral and social condition of the clergy by the reformation of existing schools and the establishment of new ones. He provided for the poor, and rebuilt decayed churches and monasteries. During the incursion of the Hungarians and the siege of Augsburg 955, he sustained the courage of the citizens, compelled the Hungarians to withdraw, and contributed much to the decisive 