Muslims have been in Spain for a while and now they are a threat to the French.
During the Battle
Abd er Rahman, who was the muslim governor of Spain, marched towards the Frankish Border to plunder the lands.
End of Battle
The Franks had themselves put on the slightly higher ground and formed a phalanx-like formation. The Arabs had cavalry with lances. They had many minor skirmishes, but on the seventh day, the Arabs couldn't postpone the small battles any longer. Their light clothing stood no chance to the cold European winter that was to come. They started the cavalry charges that day.
Hundreds of Years Later...
The Franks were winning. This a rare instance when an army withstands cavalry charges. A light cavalry unit went around the battle to plunder the Arab camp. They took back gold and freed slaves.
This raid forced the majority of the army to go into confusion. Many troops went back to save their loot. Abn er Rahman tried to get his army back together unsuccessfully. Finally, after defending for most of the time, the Franks attacked and killed many Arab troops, including Abn er Rahman, after he was cornered. The Arabs who went back to save their loot fled in the night. They left most of it behind.
Historians are debating the location of the battle. Most historians believe it took place between the Clain and Vienne rivers. They think it is between Tours and Poitiers.