In Louis’ reign their depredations upon the coast were more incessant, but they did not penetrate into the inland country, till that of Charles the Bald. The wars between that prince and his family, which exhausted France of her noblest blood, the insubordination of the provincial governors, even the instigation of some of Charles’ enemies, laid all open to their inroads. They adopted a uniform plan of warfare both in France and England; sailing up navigable rivers in their vessels of small burden, and fortifying the islands which they occasionally found, they made these intrenchments at once an asylum for their women and children, a repository for their plunder, and a place of retreat from superior force. After pillaging a town, they retired to these strongholds or to their ships; and it was not till 872 that they ventured to keep possession of Angers, which, however, they were compelled to evacuate. Sixteen years afterwards, they laid siege to Paris, and committed the most ruinous devastations on the neighbouring country. As these Northmen were unchecked by religious awe, the rich monasteries, which had stood harmless amidst the havoc of Christian war, were overwhelmed in the storm. Perhaps they may have endured some irrecoverable losses of ancient learning; but their complaints are of monuments disfigured, bones of saints and kings dispersed, treasures carried away. St. Denis redeemed its abbot from captivity with 685 pounds of gold. All the chief abbeys were stripped about the same time, either by the enemy, or for contributions to the public necessity. So impoverished was the kingdom, that in 860 Charles the Bald had great difficulty in collecting 3000 pounds of silver, to subsidise a body of Northmen against their countrymen. The kings of France, too feeble to prevent or repel these invaders, had recourse to the palliative of buying peace at their hands, or rather precarious armistices, to which reviving thirst of plunder soon put an end. At length Charles the Simple, in 918, ceded a great province (Neustria), which they had already partly occupied, partly rendered desolate, and which has derived from them the name of Normandy. Ignominious as this appears, it proved no impolitic step. Rollo [Rolf or Hrolf an exile from Norway], the Norman chief, with all his subjects, became Christians and Frenchmen.[d] France would have only had to congratulate herself upon the assignment she had been compelled to make to the Normans, had the Treaty of Saint-Clair ratified peace forever between the kingdom and this nation of pirates. Unfortunately such was not the case, and for a considerable time the Normans continued to add their ravages to the burden of the many sacrifices France had made, of all the calamities she had experienced.