He took over day-to-day administration of Rome, reorganizing estates and managing them in such a way as to generate extra revenue to feed the poor.
Negotiated a truce with the Lombards invading the Italian peninsula.
Exerted authority outside of Italy, writing letters to settle disputes as well as to offer financial assistance to distant churches.
Charlemagne won most of the 53 campaigns that he overtook during his reign.
He established himself as a leader and reformer of the church (he was pious).
He knew the importance of education and recognized the worth of scholars like Alcuin.
He also energetically sponsored learning by establishing schools and hiring scholars.
He put noblemen in charge of the various provinces he controlled and tried to use laws to bring order to his lands.
He required his noblemen to attend 2 annual assemblies in Constantinople.
He traveled frequently throughout his land to spread his influence/rule.
The traveling agents (representatives) came in pairs - one bishop and one nobleman (who looked after the province) to represent both the secular and religious arms of his kingdom.
These traveling agents had high expectations from Charlemagne because he knew that his rule depended on the obedience of his subjects.
He forced the Saxon leader to convert to Christianity after crushing Saxon armies in 785.
He established priests and monks in the conquered Saxon lands.
He punished relapses into paganism and instances of other religious disobedience as treason.