Easter festival held at Aix-la-Chapelle 30 March 951. Otto formed his plans in close consultation with his brother Henry, now his most trusted adviser, whose brilliant campaigns against the Hungarians, resulting in the acquisition of the march of Aquileia, gave additional weight to his councils. Liudolf, on the other hand, was apparently not taken into the king's confidence: indignant at his exclusion, jealous of his uncle, impetuous and anxious to make a name for himself on his own account, he determined to anticipate his father. He rapidly crossed the Alps with a small army of Swabians; but his expedition was a complete failure and before long he returned to sow the seeds of rebellion, the news of which recalled Otto, who had assumed the title of King of the Lombards at Pavia and taken Adelaide as his wife, in haste to Germany. It was not only disappointment at his failure in Italy that led Liudolf to rebel against his father. Otto's second marriage was not likely to be to his son's advantage; it would lead to a new circle at the court in which he would take but a secondary place; he might even look to being ousted from the succession by the offspring of this new alliance – an event which in fact occurred, for it was Adelaide's son, Otto, who was designated as the successor to the total disregard of the claims of his nephew and namesake, the son of Liudolf. The plans for the rebellion were formed at a Christmas gathering held at Saalfeld; the place is significant, for it was there that Henry had divulged to his friends his designs against Otto in 939. Among the conspirators was Frederick, Archbishop of Mayence, whose implication in the previous rebellions of 939 and 941 was more than suspected. He had been employed as Otto's envoy to the court of Pope Agapetus and the failure of his mission may have led to a rupture with Otto.
The news of this ominous assembly was the immediate cause of Otto's return to Germany. He crossed the Alps in February 952 and by Easter was again in Saxony. Conrad, Duke of Lorraine, was left behind in Italy to complete the overthrow of Berengar. But instead of pursuing the advantage which Otto had already gained, he made terms with Berengar and returned with him to Germany to obtain the king's ratification of his arrangements. They found the court at Magdeburg. Otto was, however, far from satisfied: he had counted on the complete subversion of Berengar. For three days the latter was not permitted to approach the royal presence and even then, through the counsel of Duke Henry, he was "barely granted his life and a safe return to his country." The final settlement with regard to Italy was postponed to a meeting to be held at Augsburg. On 7 August the diet met in the spacious Lechfeld which extended to the south of the city. Franks, Saxons, Swabians, Bavarians, Lombards, and even ambassadors from the Byzantine court attended the gathering, to which a contemporary annalist assigns the imposing Frankish title of Conventus publicus. There Berengar and his son Adalbert took the oath of homage and fealty and, by the solemn
