Charlemagne, most likely born in either 742 or 747 (both commonly accepted dates), was the son of Pepin the Short: King of the Franks. Although Pepin controlled a very large portion of Europe, there were, at the time, many other empires of great strength; for example, Byzantine. When the time of Pepin's death arrived in 768, a family rule had already been set up, enabling Charlemagne and Carloman (Charlemagne's brother) to assume divided kingship of the Frankish Kingdom. The two brothers did not get along exceptionally, and a likely war between the two was avoided with the death of Carloman in 771. This left the reunified Frankish Kingdom, and what soon came to be the Carolingian Empire, in the hands of Charlemagne.
Throughout the entirety of Charlemagne's reign, numerous conquests were undertaken, the majority of which were led by Charlemagne himself. Early in Charlemagne's sole reign, a request was sent for the aid of the Franks against Lombardy (since the Lombards were invading the papal states), located on the Italian peninsula. Charlemagne soon captured Pavia, a fortified city of Lombardy, and undertook kingship of the Lombards. Charlemagne held extensive conquests and campaigns against the Saxons (lasting approx. 30 years), Italy, Spain/the Moors (the only goal he failed to accomplish), Bavaria, the Avars, and the Slavs. Charlemagne was no doubt a strategic and fierce warrior; his leadership could not be mistaken.
Charlemagne's biographer was Einhard (also Eginhard), whose work was simply titled: (translated) "The Life of Charlemagne". It is this work which the most accurate information of events correlating to Charlemagne can be derived from; however, some minor aspects of Charlemagne's character and situations involving Charlemagne (for example, his daughter's immoralities) may be biased so as to not embarrass the king. Charlemagne was known to be a very devout Christian and protector of Christianity. Also, as Charlemagne was illiterate (due to a lack of education as a youth), he sought an education not only for himself, but also for his empire. Charlemagne created a educational center at the city of Aachen, causing the flourishing of scholarship throughout Western Europe. Building projects, such as cathedrals, bridges, and other public structures, were also encompassed in Charlemagne's accomplishments.
Charlemagne is recognized in history, and dubbed "the Great", for his extraordinary ability to escape the typical; he wasn't an all out warrior like Attila the Hun; however he also wasn't restricted to just education. Charlemagne was not just the conquerer, but the educator and the innovator.
Collins, Roger. Charlemagne. University of Toronto Press, 1998.
Einhard. The Life of Charlemagne. Kessinger Publishing, 2004.