In the spring of 778 the Christian army in force, containing contingents of Lombards and Bavarians, as well as Franks, crossed the Pyrenees, part of it passing into what afterwards became the Kingdom of Navarre, while the second division moved along the Mediterranean coast. Both were to meet at Saragossa, but before the junction was made Charles laid siege to Pampeluna, which had previously belonged to the small Christian kingdom of the Asturias. The city was taken, and at Saragossa hostages were received to guarantee to the Franks the possession of certain towns between the Ebro and the Pyrenees. With this inconclusive result the aggressive part of the campaign ended. Probably Charles hesitated to penetrate further into the country after hearing that Abderahman had lately defeated an army of Berbers who had come over to Spain to help the cause of the Abbaside Caliph. It was now evident that the prospects of the opponents of the Ommayad house were anything but brilliant, and it must have seemed advisable for the Frankish army to withdraw from Spanish territory. Summer had already begun before Charles turned his face homeward, after leveling the walls of the city of Pampeluna to the ground to prevent its inhabitants from revolting against him. It was during this retreat that the famous disaster befell the arms of Charles, to which literary history has given an importance beyond its real deserts. On the 15th of August, at Roncesvalles, while the main army was slowly winding its way among the defiles of the mountains, the Basques applied to the Franks the guerrilla tactics they had successfully used against all the invaders of Spain, Roman, Gothic, and Moslem in turn. They made a sudden attack on the rear guard, and this division of the Frankish army was utterly cut to pieces. Many of the closest followers of Charles here met their death, among them Roland, prefect of the march of Brittany, of whom we know nothing apart from this brief notice in the contemporary histories, but whose exploits were celebrated in popular legend, where, under the glamour of poetical description, he has come to occupy a place as a warrior and hero almost the equal of Hector.