In Southern Italy, the beginning of the tenth century saw the end of a long era of war and the beginning of a long phase of stabilty, probably due to a satisfactory redistribution of resources at the heart of the political entities that resulted from the fragmentation of the old Grand Duchy of Benevento. But this equilibrium began to experience crises between the end of the tenth and the first decade of the eleventh century, when the stage was populated by new actors, the Normans. Their confrontation with the more ancient political subjects of the Mezzogiorno figured more as open conflict than as simple competition effected by shared norms. The definitive Norman implantation simplified the situation, eliminating the old Lombard and Byzantine powers but at the same time was accompanied by a fragmentation of the political situation in the form of lordships. In a much transformed context, the confrontation of cultures continued to be more conflictual than competitive, as had been the case during the tenth century. Only with the birth of the Kingdom of Sicily, and a real court that became the center of a large and integrated political entity, did the confrontation get restructured according to often implicit rules, now shared by the parties involved, into a coopetitive form, as it had been already in ninth-century Benevento.
Lore', V. (2018). Coesione aristocratica e competizione politica. Italia meridionale, XI secolo. In G.B. Régine Le Jan (a cura di), Coopétition. Rivaliser, coopérer dans les sociétés du haut Moyen Age (500-1100) (pp. 333-344). Turnhout : Brepols.