Charlemagne achieved fame for consolidating the Frankish kingdom and then conquering Saxony in a bloody series of 18 battles, but after his death, his Holy Roman Empire passed to his son Louis the Pious. After Louis' passing, the empire split among Louis' three sons Charles the Bald, Louis the German and Lothair, which was the beginning of the growth of smaller nations in medieval Europe.
After defeating the Saxons, Charlemagne forced conversion to Catholicism on those whom he had conquered, killing the ones who would not comply. After consolidating his power by taking the crown of the Holy Roman Empire on Christmas morning in 800, he established a new monetary standard, making the liver (pound) worth 20 sous (the shilling later) and 240 deniers (which would become the penny). He split the empire into 350 counties, each with its own court, and he established the "Envoys of the Lord" to ensure loyalty throughout his lands.
The reign of Charlemagne is considered the Carolingian Renaissance because art, literature, scholarship and architecture began to flourish for the first time in centuries. Scholars copied and saved many of the classic works from Latin. While the size of the empire would shrink, the notion of strong centralized institutions within Europe would never fade again as it had after the fall of the Western Roman Empire.