It was not only in the mind of Charles that this high and holy view of the duty and power of the emperor found a place. [Sidenote: The Holy Roman Empire.] He succeeded in impressing it on his own contemporaries and on long centuries to come: with him starts the idea of the ‘Holy Roman Empire,’ which affected so deeply the whole secular and religious life of the Middle Ages. The Frankish kingship, a mere rule of force, had no exalted and spiritual meaning: the new empire represented a close and conscious union of Church and State for the advantage of both. It started with the conception that the emperor should be the protector and overseer of the Church: by an unhappy development it ended in making the Pope the overseer of the State. But the generation which had seen Pope Leo on his knees ‘adoring’ the majesty of the great Charles, could not have foreseen the day when the successor of Charles should humbly wait for hours before the unopened door of the successor of Leo, or beg as a favour the privilege of holding his stirrup. A new age then commences in Europe with the coronation of Charles the Great. The reign of pure barbaric force is ended: there follows a time when the history of Europe is complicated by the strife of ideas no less than by the strife of armed nations. For the future we must always be on the watch to detect the influence on politics of the ideal conception of Christendom as a great empire, under a single ruler chosen by God to sway the sword, and the rival conception of it as a great Church under a single Patriarch at Rome, appointed to hold the keys of heaven and hell, and to guide kings in the way they should go. The internal government of the vast realm of Charles was a difficult problem. [Sidenote: Charles and his sons.] In his own lifetime the great king provided for it by delegating his authority in certain large sections of it to his sons: we have already spoken of his nomination of Charles, Pippin, and Lewis to be kings in Neustria, Italy, and Aquitaine. Charles contemplated the possibility of a single empire existing while yet many of its parts should be governed by vassal sovereigns. In his own time the plan worked well enough: he did not, perhaps, foresee that the problem would be far harder in the next generation, when the homage and obedience of the lesser kings would have to be paid to a brother, an uncle, and at last to a mere distant cousin.