During these hard times, Charlemagne and his Frankish forces in the eighth century A.D. crushed the last of the Barbarian kings of Italy . But, this reprieve was short lived. In giving thanks, Pope Leo III made a terrible mistake that was to lead to another prolonged period of disharmony and conflict. To secure Charlemagne's loyalty, the Pope gave him the title of Holy Roman Emperor. Most of Italy came under the rule of the Emperor, and this led to future conflicts between the Emperor and the Pope that was to drive the Italians into their own version of a civil war. The population of Florence was divided over their loyalty between the two factions. And so in Florence different factions formed, some Guelf who supported the Emperor, and some Ghibelline who followed the Pope.