The imperial policy of Charles the Great constitutes a preface to the history of the later Middle Ages. He holds the balance between nascent forces which are to distract the future by their conflicts. He pays impartial homage to ideas which statesmen less imperious or more critical will afterwards regard as irreconcilable. He is at one and the same time an autocrat, the head of a ruling aristocracy, and a popular ruler who solicits the co-operation of primary assemblies. From the highest to the lowest his subjects must acknowledge their unconditional and immediate allegiance to his person; yet he tolerates the existence of tribal duchies, he revives the Lombard kingdom, and creates that of Aquitaine, as appanages for his younger sons. He fosters the growth of territorial feudalism, and lends the sanction of royal authority to the claims of the lord upon his vassal; but simultaneously he contrives expedients for controlling feudalism and stifling its natural development. He exalts the Church, and he enslaves her. He is there to do the will of God as expounded by the clergy; but he disposes of sees and abbacies like vacant fiefs, he dictates to the Pope, he interferes with the liturgy, he claims a voice in the definition of dogma and the wording of the creed. Finally, and most striking, there is the antithesis between the two aspects of his power, the monarchical and the imperial.

The Franks left to Europe the legacy of two political conceptions. They perfected the system of barbarian royalty; they outlined the ideal of a power which should transcend royalty and embrace in one commonwealth all the Catholic kingdoms of the West. On the one hand they supplied a model to be imitated by an Egbert, a Henry the Fowler, a Hugh Capet. On the other hand they inspired the wider aims of the Ottos and the Hohenstauffen. It is therefore worth our while to understand what a Carolingian king was, and what a Carolingian Emperor hoped to be.

The king's power was based upon three supports: the general allegiance of his subjects, the more personal obligations of the vassals who were in his mund, the services and customs of the tenants on the royal demesne. It is from these last that he derives his most substantial revenue. He is the greatest landowner of his realm, until in the ninth century he dissipates his patrimony by grants of hereditary beneficia. The farming of the demesnes is an important branch of the public service; they are managed by bailiffs, who work under rules minutely elaborated by the king in the form of edicts, and who render their accounts to a minister of state, the Seneschal or steward of the household. The king is further the fountain of justice, the guardian of public order, the protector of peaceful industry and commerce. Accordingly he derives large profits from the fines of the law-courts, the forfeitures of criminals, the tolls of highways and markets, the customs levied at seaports and at frontier towns. In the exercise and exploitation of his prerogatives he is assisted by functionaries of whom most are household officers: the Chamberlain who keeps the royal hoard; the Constable (comes stabuli ) who marshals the host; the Seneschal, or High Steward, who controls the demesnes; the Protonotary, by whose staff the royal letters and all documents of state are written out; the Arch-chaplain, to whom ecclesiastical suitors bring their petitions and complaints. Finally there are the Counts of the Palace, appointed from the chief races of the realm, who exercise the king's appellate jurisdiction in secular cases. But the king is bound by custom to govern with the counsel and consent of his great men - a Germanic tradition which no after growth of respect for Roman absolutism can destroy. A select body of influential nobles deliberates with the king on all questions of national importance. Their decisions are submitted for approval to a more general assembly (Mayfield), held annually in the spring or summer. By this assembly the military expedition of the year is discussed and sanctioned; here also are promulgated royal edicts (capitula).

The ordinary freeman, upon whom falls the ultimate burden of military service, has no voice in the debates of the Mayfield; but ordinances affecting the old customary laws of the several races which make up the kingdom (Salians, Ripuarians, Saxons, etc.) do not take effect till they have been accepted by popular assemblies in the provinces which they concern. And such revisions are infrequent. The royal prerogative in legislation is limited by a popular prejudice, which regards the customary law as sacred and immutable. The Capitularies are chiefly administrative ordinances; the "law of the land," which is the same everywhere and for all persons, is an ideal to be realised in England alone of medieval states. Elsewhere the king's law is a supplement, a postscript; the privilege of the free man is to live under the law of his province, his lord's fief or his free city.