There is not much Charlemagne did not do to help Europe. When he was born circa 744, Europe was still mired in the Dark Ages. It was a time of continual strife and little education or social advancement. Charlemagne became King of the Franks and sole ruler after his brother's death. From this platform, he would bring Europe to civilization and enlightenment through violence.
Charlemagne waged many bloody campaigns to unite the Germanic tribes and bring Christianity to the many tribes of Europe. In 1800, he was granted the title of Holy Roman Emperor by Pope Leo III, although it was not a title he used much for fear it would create the impression he relied upon the Pope for power. When Charlemagne died, his empire stretched across much of Europe and his influence was felt from the peasant class through the nobles.
Charlemagne did not just encourage Christianity; he demanded it and ordered the death of anyone not practicing it. However, he was much more generous in other areas of society. One of his greatest achievements was to abolish the gold standard of Europe and install a united silver standard. This enabled easier trading across Europe and stimulated otherwise stale economies. Charlemagne was a devoted father who encouraged education in his family and for everyone. He gave more power to peasants and served as an overlord for noblemen, to ensure they were treating their subjects fairly.
Charlemagne helped Europe by providing hope. He standardized currency, encouraged education, united various tribes and gave power to the people. This aided in the recovery of Europe from the Dark Ages.