The administrative coherence of the Norman kingdom was first described by Rosario Gregorio at the time of the French revolutionary wars. He attributed to Roger II the formulation of a political structure which reserved to the sovereign ruler sole responsibility for general wellbeing and public order. He examined, but rejected, the idea that the Normans erected the monarchy on the basis of any vestiges of Byzantine or Muslim institutions, and insisted on Norman originality. He also made several pointed comparisons between Roger II and William the Conqueror, who could impose his new order at one sweep by virtue of his conquest. Not content with recognising that the Norman conquerors in Italy had brought their own legal customs with them, Gregorio argued that Roger even willingly adopted some of the political institutions devised by William in England. Feudal monarchy is here presented in the garb of enlightened despotism.

The twelfth-century text which sheds most light on the inner workings of the southern monarchy is the Liber de Regno, and it portrays a kingdom where the kings count for less than their great ministers. Its view of events in the 1160s could hardly be sharper. It would be easier to assess if its author could be placed. No other Latin writer of the twelfth century, or indeed of the middle ages, writes Latin with such classical assurance, or of public affairs with comparable detachment or firmer commitment to a sense of how they should be honourably managed.