Two comets appeared around the sun, striking terror into all who saw them. A swarm of Saracens ravaged Gaul with horrible slaughter
The mythology of the Franks as defenders of the faith against the Saracen threat had a long history. In 732 the new emir of Cordoba Abd ar-Rahman, so it was written, led a massive Saracen army of between 30-50,000 men over the Pyrenees into France. His intention was to overrun France as his predecessors had done Spain, twenty years earlier.
Eudes, duke of Aquitaine met the vast army but was considerably outnumbered.
The Arabs had already made several previous incursions into France with mixed success. In 721 they had been defeated at Toulouse, but four years later had managed to come within a hundred miles of Paris, setting fire to the city of Autun as they retreated. In 732 however, the invading force was a great deal more substantial and threatening.
According to a Spanish chronicler of the time, Abd ar-Rahman “joined battle with Eudes on the other side of the rivers Garonne and Dordogne”, leaving the Aquitanians “disastrously bloodied” and the city of Bordeaux ravaged.
The mighty Saracen force advanced north from Bordeaux towards Poitiers. There they plundered the basilica of the patron of the city, Saint Hilaire. The army moved on towards Tours the greatest Frankish city and the shrine of their most venerated guardian, Saint Martin.
“Abd ar-Rahman decided to despoil Tours”, the chronicler continued, ”by destroying its palaces and burning its churches. There he confronted the consul of Austrasia by the name of Charles”.
On a flat plain somewhere between Poitiers and Tours, by the side of the old Roman highway, the two armies met. Eudes of Aquitaine had made an oath of fealty to the Frankish leader Charles Martel who led their joint forces.
“The northern peoples remained as immobile as a wall, holding together like a glacier in the cold regions. In the blink of an eye they annihilated the Arabs with the sword”. Thus, the Spanish historian, writing just thirty years after the event, described the battle which put an end to Arab plans of extending their hegemony over the whole of Europe.
Out of this victory, a new dynasty emerged, the Carolingian. Charles, whose victory earned him the name Martel, the Hammer, was nominally the so-called Mayor of the Palace at the court of the weak Merovingian king. His victory at the battle of Poitiers sealed his power base and paved the way for his son Pepin to become king of the Franks and his grandson Charlemagne, to becoming Holy Roman Emperor.
Historians are divided as to the real significance of the Battle of Poitiers but it nevertheless, entered the annals of legend. History and mythology became entwined and difficult to separate, each acting on the other.
In the eleventh and twelfth centuries the Chansons de Geste, the epic poems 
which recounted the great deeds of the Carolingian monarchs and their heroic knights, painted the Franks as the defenders of Christendom. They were cast as the Chosen People and their Christian struggle against the pagan Saracens explicitly linked them to the Israelites of the Old Testament, the Moors now become Ishmaelites and Chaldeans.
Not only did the Song of Roland and the History of Charlemange and Roland draw on this legendary material, but so too did the Pilgrim’s Guide. All three placed the Compostelan pilgrimage firmly within this mythological tradition.