The calm, thus wisely employed, did not last long. Charlemagne was soon aroused from his peaceful occupations to put down a revolt of Tassilo, Duke of Bavaria, as well as a meditated attack upon Italy by Adalgisus, the son of the deposed Lombard king, Desiderius, who was assisted underhand by the Greek empress, Irene, and had besides formed a secret alliance with the Duke of Beneventum. Tassilo, being seized, was condemned to death by the great council. He appealed to the clemency of the king, who, ever averse to shed blood, mitigated the sentence into a lifelong seclusion from the world in a cloister. Adalgisus was met by the Duke of Beneventum, not to assist him, as he had expected, but to oppose him, for the duke had in good time discovered that loyalty was more likely to prosper than treason. He therefore joined the army of France under Grimwold, and in the battle which succeeded the Greek forces were entirely routed, and Adalgisus disappears from the busy scene.
The empire of Charlemagne was next to be assailed by the Huns, not the same people whose fathers had fought under Attila, though probably descended from the same stock. Upon the death of that ferocious conqueror, the tribes whom his talents had kept united, again sundered. Shortly afterward a warlike nation, calling themselves Avars, approached the northern parts of Europe, having been driven from their native country by the Turks. They spread rapidly, acquiring territory and power, until they were invited by Tassilo to aid him in his meditated treachery. They lost more than one battle against the Franks, but neither their own defeat, nor the total overthrow of their ally, made any change in their purposes. They persisted; fought a hard battle, and were so utterly routed, that they drew back and remained quiet for a while, in order to collect their strength before venturing upon a fresh contest with their tremendous adversary, who, on his part, was no less desirous of a respite for the same object. Little rest, however, was allowed him. No sooner had he beaten back these Huns, than he had to contend with a new enemy, the Weletabes, a Slavonian tribe inhabiting the northern part of Germany, near Brandenburg and Pomerania, from the Elbe to the Baltic. In themselves they might not have excited much alarm, but, if they met with only a temporary success, their example might have been fatal, by rousing the Saxons, who still with reluctance submitted to the yoke imposed upon them. The king, therefore, without loss of time, met and defeated the Weletabes; when he received them into grace, and ever afterward found them faithful.
Having freed himself from this peril, Charlemagne next found that he must turn his arms against the Huns of Hungary, which appears to have been defended by them after a singular fashion. The whole country was surrounded by nine circles of double palisading, formed of trunks of trees twenty feet in height. The interstices of the palisade were twenty feet wide, filled with stone and lime compacted, the top being covered with earth, and planted with shrubs. At the distance of twenty Teutonic, or forty Italian miles, was a second fortified line of the same kind; and thus the circles were repeated, the circumference always narrowing till you came to the innermost, or ring, in which the Avars kept all their wealth, the accumulation of centuries of rapine. Such, at least, is the account, however improbable, handed down to us by an historian of the day.
In the outset fortune favored Charlemagne as usual. He took the first three of the defensive circles sword in hand, and laid waste the country to the junction of the Raab with the Danube, while his son Pepin had met and routed their army in another quarter. But unhappily a pestilential disease broke out among the horses, who died by thousands, and he was obliged to retreat, unpursued, however, by the Avars, their surprise and terror not having yet subsided.
In the doubtful lull that followed, a conspiracy was raised against the life and throne of the monarch, in which his natural son, Pepin the Hunchback, was implicated. It was discovered in time, and all the conspirators were put to death, with the exception of Pepin, who was confined for life within a monastery.
Scarcely had the king escaped this danger, than he was alarmed by news that the Saxons had revolted, and uniting themselves with the Huns, had given a bloody defeat to his cousin, Theodoric. Close upon this came other tidings of equally evil import. In the late campaign against the Huns, Charlemagne had called to his aid his son Pepin, King of Italy, who, notwithstanding he was himself embroiled with Grimbald, Duke of Beneventum, did not hesitate to obey. To reward this prompt obedience, Charlemagne early in the winter had despatched another son, Louis, King of Aquitaine, to the help of his brother, when the Saracens took advantage of the latter's absence to attack his frontiers, and even penetrated to Narbonne before any forces were ready to oppose them. From this expedition they returned home laden with plunder, and satisfied with this success, remained for a while in quiet. Charles therefore had a brief respite to turn against the Saxons; and as he had hitherto found all his precautions unavailing to keep them within the bounds of good order, he broke up the nation, and transported an immense number of the most turbulent to a distance from their own country. Multitudes of men, women, and children were dispersed over France, and not a few were transported to Brabant and various parts of Flanders.
About this time, 793, the first collision took place between the Franks and the piratical Northmen.
It would be alien from our present purpose to follow Charlemagne step by step in his march of conquest and civilization. We need only say in general terms, that he drove back the Arabs, reduced the Huns, became the friend of Haroun al Raschid, his only rival in the paths of greatness, and effectually protected his long line of coast from the attempted incursion of the Northmen. It is said that upon one occasion he arrived at a certain port just as the pirates were preparing to land; but the moment they by some means learnt the presence of the monarch, they immediately fled in terror at his mere name. He remained gazing on the departing vessels, while the tears rolled down his cheeks. His nobles could not help showing surprise at such unusual emotion in the monarch, which being observed by him he exclaimed, "I weep not, my friends, because I myself fear these miserable savages; but I weep that they should dare to show themselves upon my coast while I am living, for I foresee the evils they will bring upon my people when I am dead."
It was always an object of first importance with Charlemagne to support the papal authority, as holding out the only means of spreading Christianity, which he justly considered the most effectual instrument he could employ to enlighten and civilize the world. An attempt had been made to mutilate the Pope, and thus disqualify him for his office, by Campulus and Paschal, two disappointed aspirants to the papacy; but he escaped from their hands and brought his complaints before Charlemagne. The conspirators then attempted to justify the deed, by accusing the Pope of atrocious crimes; and the king calling to his aid certain of the Roman prelates, proceeded to sit in judgment on him. The prelates, however, declared that by all the canonical rules they could not judge their superior; and Leo therefore was allowed, according to an old custom, to purge himself, by a solemn oath, of the crimes which had been laid to his charge.
Many motives of policy at this time induced the Pope to set up an emperor of the West in opposition to the Eastern Empire. It was Christmas-day, when, with the rest of the Catholic world, Charlemagne presented himself in the church of St. Peter. At the desire of the Romans he was dressed in the long robe of the patrician, and unsuspicious, it is said, of the honor intended him, knelt at the high altar; but, just as he was about to rise, Leo advanced, and suddenly placed upon his head the crown of the Western world, amidst the popular acclamations, "Long life and victory to Charles Augustus, crowned by God, great and pacific Emperor of the Romans!"