In 732 Leo took a more practical step for reducing the Pope to obedience. He fitted out a great armament in the ports of Asia Minor, which was to sail to Italy, to recover by force of arms the lost regions of the Exarchate, and to arrest Gregory III. and send him in chains to Constantinople. But the fates were against the restoration of imperial authority in the West: the fleet was completely wrecked by a storm in the Adriatic, and the fragments of it which reached Ravenna effected nothing. This was the last serious attempt of the empire to recover central Italy. [Sidenote: Last effort of Leo to reconquer Italy, 732.] Henceforth the Popes went their own way, while the exarch, penned up in the single fortress of Ravenna, awaited with trembling the outbreak of the next Lombard war—a war which would certainly sweep away him and his shrunken Exarchate. But for eight years after the treaty of 730, king Liutprand maintained peace over all Italy. He was a pious prince, and a respecter of the papacy, to which he had even made a grant of territory, ceding the town of Sutri in Tuscany, which he had captured from the exarch in the war of 728-30. His reign was a time of prosperity for Lombardy: the southern dukes were compelled to obey orders from Pavia: the Slav and Avar were kept back from the northern marches, Liutprand also kept up his friendly relations with Charles Martel, the great Mayor of the Palace in Gaul. When Charles was looking about for a neighbour sovereign who should, according to old Teutonic custom, gird with arms and clip the hair of his son Pippin on his arrival at manhood, he chose Liutprand to discharge this friendly office. On the invasion of Provence by the Saracens in 736-7, Charles asked the Lombard for the aid of his host, and Liutprand crossed the Alps and joined in expelling the infidels from Aix and Arles.