”To Martel’s contemporaries, however, it was hardly so significant. At the time, the entire region was wracked with similar battles, usually between Christian princes as the Carolingians fought to establish control over Aquitaine. There had been many battles fought between Muslims and Christians in southern France, some won by each side.
One chronicler even blamed the Christian Duke of Aquitaine, Eudo, for causing the battle by seeking to ally with the Muslims north of the Pyrenees in Septimania who themselves were seeking independence from the Arab rulers in Spain. Many of the battles fought by Charles Martel were as much aimed at troublesome Christian princes as they were at Muslim interlopers who were relatively few in number. Most contemporary historians were unimpressed by the Islamic threat to southern France and the Mediterranean, seeing them as pagan barbarians and a nuisance but not an existential threat.
There were a number of other factors which led to the halting of the Muslim advance into Western Europe. While they fought in the name of religion, the Muslims at Tours were chiefly concerned with easily acquired plunder. The Franks proved too much of a nut to crack, especially considering there were more easily acquired riches elsewhere. The climate of central France may have been uncongenial to the Arab and Berber invaders who were also reaching the limits of their manpower. Meanwhile, the invasion of Spain was not even complete as resentful Visigothic princes in the northwest remained resistant to the Islamic invaders.
While a Muslim victory at Tours would likely have had some significance and possibly led to a longer period of Islamic forays into southern France, it was only one of many battles fought in the region during this time period. In fact, it’s likely the Muslim tide would’ve died off regardless, absent larger historical divergences. -- http://listverse.com/