Charles Martel
Charles Martel (c. 688 – 22 October 741) was the de facto ruler of the nation that became France. Martel was not his surname. European surname did not come into use for several hundred years. Martel was a kind of nickname - meaning "hammer" - as he was regarded as a great warrior.
Charles was the grandfather of the ruler now known as Charlemagne, formally known, during his lifetime, as Carolus Magnus - Latin for Charles the Great.
Charles's official title was Mayor of the Palace - nominally the subordinate of the Merovingian King of France.
During a period of muslim expansion muslims had wrested control of what is now Spain, and tried to gain control of areas in the south of the Frankish lands, only to be decisively defeated by Charles, in 713, in the Battle of Tours.
One of Charles's sons, Pepin the short, finally deposed the last king of the Merovingian dynasty, and assumed kingship in his own name.