This he accomplished in part by donating lands and money for the foundations of abbeys such as Echternach.
In the following decade Charles led the Frankish army against the eastern duchies.
He dealt with the ongoing conflict with the Frisians and Saxons to his northeast with some success, but full conquest of the Saxons and their incorporation into the Frankish empire would wait for his grandson Charlemagne.
Most importantly, instead of concentrating on conquest to his east, he prepared for the storm gathering in the west.
Well aware of the danger posed by the Muslims after the Battle of Toulouse, in 721, he used the intervening years to consolidate his power, and gather and train a veteran army that would stand ready to defend Christianity itself at Tours. It was in the Battle of Tours that Charles received the nickname "The Hammer" for the merciless way he hammered his enemies. This battle will always remain one of the great events in the history of the world, as upon its issue depended whether Christian Civilization should continue or Islam prevail throughout Europe. (Catholic History, Volume III)
After his victory at Tours, Martel continued on in more triumphant campaigns to drive other Muslim armies from bases after they again attempted to get a foothold in Europe. The defeats Martel inflicted on the Muslims were absolutely vital in that the split in the Islamic world left the Caliphate unable to mount an all out attack on Europe through its strength.
These victories were very important, had Charles lost these battles,
Europe would be an Islamic nation instead of Christian. (Catholic History, Volume III)
The final four years of Charles' life, was more peaceful than most of it had been and much of his time was now spent on administrative and organisational plans to create more efficient state. Charles set about integrating the outlying realms of his empire into the Frankish church. Charles was that rarest of commodities in the Dark Ages: a brilliant stategic general, who also was a tactical commander. Charles had the last quality which defines genuine greatness in a military commander: he foresaw the dangers of his foes, and prepared for them with care; he used ground, time, place, and fierce loyalty of his troops to offset his foe's superior weaponry and tactics; third, he adapted, again and again, to the enemy on the battlefield, cooly shifting to compensate for the unforeseen and unforeseeable.
Charlemagne: Charlemagne was the son of Pepin and the Grandson of Charles
Martel. When Peppin died he divided the dynasty among his two sons Carloman and Charlemagne.
Pepin invaded Italy to protect the pope against the Lombards in 756 and after 760
Pepin's main military efforts went into the conquest of Aquitaine, the lands south of the Loire River. This is important because when Pepin died in 768, still fighting with the Lombards, Charlemagne sought an alliance with the Lombards by marrying (770) the daughter of their king, Desiderius. (Charlemagne: Encyclopedia, Medieval History)
However, when Carloman died suddenly in 771, Charlemagne then seized his territories, but Carloman's heirs took refuge at the court of Desiderius. By that time Charlemagne had divorced his wife, and Desiderius was no longer friendly.
Believing in the power of the sword to extend and defend Christianity, he quickly concluded the war in Aquitaine, defeated the Lombards, seized their crown, and made his son sub-king of Italy. There followed successful campaigns against the Saxons, whom he converted to Christianity. That campaign had some initial success but was to drag on for 30 years, in which time he conducted many other campaigns as well. Charlemagne's reputation was such that the patriarch of Jerusalem named him protector of the holy places and gave him the keys to the Holy Sepulcher. (Charlemagne: Father of a Continent; Alessandro Barbero) He fought in Spain in 778, and between 791 and 796
Charlemagne's armies conquered the empire of the Avars.
On Christmas Day, in 800, Charlemagne knelt to pray in Saint Peter's Basilica in Rome. Pope Leo III then placed a crown upon his head, and the people assembled in the church acclaimed him the great, pacific emperor of the Romans. Pope Leo's act was certainly something out of the ordinary. No pope had ever taken such power upon himself. He assumed the right to appoint the emperor of the Romans. The pope had risen above his protector. (Daily Life in the World of Charlemagne; Pierre Riche)
Charlemagne established a more permanent royal capital than had any of his predecessors. At his court he gathered scholars from all over Europe, the most famous being the English cleric Alcuin of York, whom he placed in charge of the palace school.
Administration of the empire was entrusted to some 250 royal administrators called counts. Charlemagne issued hundreds of decrees, called capitularies, dealing with a broad range of topics from judicial and military matters to monasteries, education, and the management of royal estates.
Charlemagne is important not only for the number of his victories and the size of his empire, but also for the special blend of tradition and innovation that he represented.
On one hand, he was a traditional Germanic warrior, who spent most of his adult life fighting. In the Saxon campaigns he imposed baptism by the sword, and he retaliated against rebels with merciless slaughter. On the other hand, he placed his immense power and prestige at the service of Christian doctrine, the monastic life, the teaching of Latin, the copying of books, and the rule of law. His life, held up as a model to later kings, thus embodied the fusion of Germanic, Roman, and Christian cultures that became the basis of European civilization. (Daily Life in the World of Charlemagne; Pierre Riche)
Catholic History, Volume III
Constantine the Great, Encyclopedia, Medieval History