(931–936), and the subsequent Popes, in strict leading strings, and retained his power until his death in 954. His dreams of hereditary power seemed established when his young son Octavian succeeded him as a ruler of Rome, and in 955 also ascended the papal throne as John XII. [Sidenote: John XII., 955–964.] But the new Pope, who thus united the ecclesiastical with the temporal lordship of Rome, looked upon things purely with the eye of a skilful but unscrupulous statesman. His great ambition was to make his house supreme throughout middle Italy, and he soon found that King Berengar whose claims grew greater now that Otto was back beyond the Alps, was the chief obstacle in the way of carrying out his designs. He therefore appealed to Otto for aid against Berengar. In 957 Ludolf of Swabia was sent by his father to wage war against Berengar, but, after capturing Pavia, Ludolf was carried off by fever, and Berengar then resumed his successes. In 960 John sent an urgent appeal to Otto to come to his assistance. Otto had, as we have seen, long felt the need of the support of the Papacy in carrying out his schemes over the German Church. The wished-for opportunity of effecting a close alliance with the head of the Church was now offered by the Pope himself, and the monastic reformers, disciples of Bruno, or of the new congregation of Cluny, urged him to restore peace and order to the distracted Italian Church. [Sidenote: Otto crowned Emperor, 962.] In 961 Otto procured the election and coronation of Otto, his young son by Adelaide, as king of the Germans. In August he marched over the Brenner at the head of a stately host. On 31st January 962 he entered Rome. On 2nd February he was crowned Emperor by John XII. [Sidenote: Consequences of the revival of the Roman Empire.]