likely that Crescentius II played a key role in the process. For a number of years, Crescentius II exercised authority over the city, severely limiting the autonomy of the pope in the process. When the Empress Theophanu was in Rome between 989 and 991, Crescentius II nominally subordinated himself to her, though he maintained his position as ruler of the city. First expedition into Italy After taking the crown in 994, Otto III faced first a Slavic rebellion, which he put down, and then an attempt by Crescentius II to seize power in Italy. When Otto III turned his attention to Italy, he not only intended to be crowned Emperor but also to come to the aid of Pope John XV, who had been forced to flee Rome. Otto set out for Italy from Ratisbon in March 996. In Verona, he became the patron of Otto Orseolo, the son of Venetian Doge Pietro II Orseolo. He then pledged to support Otto Orseolo as the next Doge of Venice, leading to a period of good relations between the Holy Roman Empire and the Republic of Venice after years of conflict under Otto II. Reaching Pavia for Easter, 996, Otto III was declared King of Italy and crowned with the Iron Crown of the Lombards. The king failed, however, to reach Rome before Pope John XV died of fever. While Otto III was in Pavia, Crescentius II, fearing the king's march on Rome, reconciled with Otto III and agreed to accept his nominee as pope. While in Ravenna, Otto III nominated his cousin and court chaplain Bruno, who was then only twenty-three years old, and sent him to Rome with Archbishop Willigis to secure the city. In early May 996, Bruno was consecrated as Gregory V, the first pope of German nationality. Despite submitting to Otto III, Crescentius shut himself in his family's stronghold, the Tomb of Hadrian, out of fear of retribution. The new supreme pontiff crowned Otto III as emperor on 21 May 996, in Rome at St. Peter's Basilica. The Emperor and Pope then held a synod at St. Peter's on 25 May to serve as the Empire's highest judicial court. The Roman nobles who had rebelled against Pope John XV were summoned before the synod to give an account of their actions. A number of the rebels, including Crescentius II, were banished for their crimes. Pope Gregory V,