'Abd-al-Raḥmân was a good general, but failed to do two things he should have done before the battle: He either assumed that the Franks would not come to the aid of their Aquitanian rivals, or did not care, and he thus failed to assess their strength before the invasion. He failed to scout the movements of the Frankish army. These failures disadvantaged the Muslim army in the following ways: The invaders were burdened with booty that played a role in the battle. They had casualties before they fought the battle. Weaker opponents such as Odo were not bypassed, whom they could have picked off at will later, while moving at once to force battle with the real power in Europe and at least partially pick the battlefield. While some military historians point out that leaving enemies in your rear is not generally wise, the Mongols proved that indirect attack, and bypassing weaker foes to eliminate the strongest first, can be a devastatingly effective mode of invasion. In this case, those enemies were virtually no danger, given the ease with which the Muslims destroyed them. The real danger was Charles, and the failure to scout Gaul adequately was disastrous. According to Creasy, both western and Muslim histories agree the battle was hard fought, and that the Umayyad heavy cavalry had broken into the square, but agreed that the Franks were in formation still strongly resisting. Charles could not afford to stand idly by while Frankish territories were threatened. He would have to face the Umayyad armies sooner or later, and his men were enraged by the utter devastation of the Aquitanians and wanted to fight. But Sir Edward Creasy noted that, Both Hallam and Watson argue that had Charles failed, there was no remaining force to protect Western Europe. Hallam perhaps said it best: "It may justly be reckoned among those few battles of which a contrary event would have essentially varied the drama of the world in all its subsequent scenes: with Marathon, Arbela, the Metaurus, Châlons and Leipzig." Strategically, and tactically, Charles probably made the best decision he could in waiting until his enemies least expected him to intervene, and then marching by stealth to catch them by surprise at a battlefield of his choosing. Probably he and his own men did not realize the seriousness of the battle they had fought, as one historian put it: "few battles