Exarchate yielded without reluctance to his civil and military power; and a foreign enemy was introduced for the first time into the impregnable fortress of Ravenna. That city and fortress were speedily recovered by the active diligence and maritime forces of the Venetians; and those faithful subjects obeyed the exhortation of Gregory himself, in separating the personal guilt of Leo from the general cause of the Roman empire. The Greeks were less mindful of the service, than the Lombards of the injury: the two nations, hostile in their faith, were reconciled in a dangerous and unnatural alliance: the king and the exarch marched to the conquest of Spoleto and Rome: the storm evaporated without effect, but the policy of Liutprand alarmed Italy with a vexatious alternative of hostility and truce. His successor Astolphus declared himself the equal enemy of the emperor and the pope: Ravenna was subdued by force or treachery, and this final conquest extinguished the series of the exarchs, who had reigned with a subordinate power since the time of Justinian and the ruin of the Gothic kingdom. Rome was summoned to acknowledge the victorious Lombard as her lawful sovereign; the annual tribute of a piece of gold was fixed as the ransom of each citizen, and the sword of destruction was unsheathed to exact the penalty of her disobedience. The Romans hesitated; they entreated; they complained; and the threatening Barbarians were checked by arms and negotiations, till the popes had engaged the friendship of an ally and avenger beyond the Alps. In his distress, the first Gregory had implored the aid of the hero of the age, of Charles Martel, who governed the French monarchy with the humble title of mayor or duke; and who, by his signal victory over the Saracens, had saved his country, and perhaps Europe, from the Mahometan