<P> Use of the term "Carolingian Empire" is a modern convention . The language of official acts in the empire was Latin . The empire was referred to variously as universum regnum ("the whole kingdom", as opposed to the regional kingdoms), Romanorum sive Francorum imperium ("empire of the Romans and Franks"), Romanum imperium ("Roman empire") or even imperium christianum ("Christian empire"). </P> <P> Though Charles Martel chose not to take the title King (as his son Pepin III would, or Emperor, as his grandson Charlemagne) he was absolute ruler of virtually all of today's continental Western Europe north of the Pyrenees . Only the remaining Saxon realms, which he partly conquered, Lombardy, and the Marca Hispanica south of the Pyrenees were significant additions to the Frankish realms after his death . </P> <P> Martel was also the founder of all the feudal systems and merit system that marked the Carolingian Empire, and Europe in general during the Middle Ages, though his son and grandson would gain credit for his innovations . Further, Martel cemented his place in history with his defense of Christian Europe against a Muslim army at the Battle of Tours in 732 . The Iberian Saracens had incorporated Berber light horse cavalry with the heavy Arab cavalry to create a formidable army that had almost never been defeated . Christian European forces, meanwhile, lacked the powerful tool of the stirrup . In this victory, Charles earned the surname Martel ("the Hammer"). Edward Gibbon, the historian of Rome and its aftermath, called Charles Martel "the paramount prince of his age". </P> <P> Pepin III accepted the nomination as king by Pope Zachary in about 751 . Charlemagne's rule began in 768 at Pepin's death . He proceeded to take control of the kingdom following his brother Carloman's death, as the two brothers co-inherited their father's kingdom . Charlemagne was crowned Roman Emperor in the year 800 . </P>

The carolingian era was marked by what type of social system