One of the great works of medieval literature is the Chanson de Roland, a twelfth century epic that recounts the destruction of Charlemagne’s rear guard at the narrow pass of Roncesvalles in the Pyrenees. The King and his army are returning from a campaign against the Moors of Spain, and twelve valiant knights, among them the King’s nephew Count Roland, ride behind them.
The Saracens descend on Roland’s men and eventually slaughter them all. In point of fact, the attackers were Basques, but the poet turned them into infidels. Roland gallantly refuses to sound his horn for help. Only after the battle, when he and his comrade Oliver are at the point of death, does he wind his horn to call for Charlemagne.
(see link at end)…Charlemagne also fought a number of times against the Arabs in Spain. He not only prevented them from settling in Southern France, as they had tried to  do in the time of Charles Martel; but he won from them a strip of their own country south of the Pyrenees Mountains. In one of these wars, the rearguard of Charlemagne’s army was cut off and slain by the mountain tribes in the narrow pass of Roncevalles. The leader of the Franks was Roland, while the leader of the enemy was called Bernardo. Long after that day strange stories grew up and poets sang of the brave deeds of Roland, and of the mighty blasts which he gave on his hunting-horn, to warn Charlemagne of the danger to his army. Three blasts he blew, each so loud and terrible that the birds fell dead from the trees, and the enemy drew back in alarm. Charlemagne, many miles away, heard the call, and hastened to the rescue; but he came too late. An old song says:
“The day of Roncevalles was a dismal day for you,
Ye men of France, for there the lance of King Charles was broke in two;
Ye well may curse that rueful field, for many a noble peer
In fray or fight the dust did bite beneath Bernardo’s spear.” Read More:http://www.mainlesson.com/display.php?author=harding&book=middle&story=charlemagne