Following the collapse of the Roman Empire under the invasion of Germanic tribes, the Lombards sought control of Italy but were opposed by the Bizantine Empire in the south. This unstable situation grew worse with a rebellion among the Lombards. As the rebellion faltered it's leaders called upon the Normans for help. They obliged and integrated themselves into the region gradually gaining control until they defeated all remaining powers in the battle of Civitate.
—David Foss