Not a generation had passed since the death of Charlemagne, and the phenomenon manifested itself, with all evidence, in the struggles between the sons of Louis the Pious to divide the empire. For the first time in 833 Germany found itself collected, as an organism in itself, under its own sovereign, with the assignment of Saxony, Thuringia, Franconia, Alamannia and Bavaria to Ludovico, who went down in history with precisely the name of Germanicus, and who was called king of the eastern Franks. Then events precipitated. On 25 June 841 Saxons, Alamanni and Bavarians fought together at Fontanetum, under Louis the German, allied to his half-brother Charles the Bald, against Lothair I, who, however, also had Saxons and Austrasians in his army. On February 14, 842, the solemn oath pronounced in Strasbourg, in the presence of the deployed armies, by Ludovico in the Romance language and by Charles in the German language, to be understood by the warriors of the respective ally, and by the leaders of the two armies in their own language, was the official recognition of the existence of the two distinct nationalities. In August 843 the Treaty of Verdun also sanctioned the independence of the reign of Louis the German, east of the Ems, the Rhine and the Aare, from the reign of France, and the independence of both from the Empire: vague and without content was the supremacy left, with the imperial title, to Lothair I.
The problem of the lands on the left of the Rhine remained. It was posed but not resolved in Verdun, assigning the dioceses of Mainz, Worms and Speyer to the kingdom of Louis the German, and creating a kind of buffer state between it and the kingdom of France. Lothair I as king, hence the name Lotharingia, between the Alps, the Jura and the Rhine to the east, the valleys of the Rhone, the Saône, the Meuse and the Scheldt to the west, while towards the North Sea it extended to include Friesland beyond the mouths of the Rhine up to the Ems and the Weser estuary. But a state of this nature, devoid of any ethnic and territorial unitary basis, could not long resist the forces that pushed Ludovico to cross the Rhine, and Charles to oppose its progress. After having been in arms against each other for twenty years, they ended up agreeing to the expenses of Lotharingia, which in the meantime had lost the lands between the Rhone and the Alps, passed (863) to the emperor Louis II. In August 870 the Treaty of Mersen marked the disappearance of the buffer state, and its territory was divided into roughly equal parts,
The language community could give the new kingdom a useful basis for building national unity above the regional and local interests, always warmly felt by Saxons, Francons, Alamanni and Bavarians. On the other hand, even in Germany the evolution of the Frankish institutes led lay and ecclesiastical offices (dukes, counts, bishops) to transform themselves into fiefdoms rooted in land ownership, and fiefdoms to evade the control of central authority as dominî autonomous territories, the phenomenon had not yet reached the development it had taken in France. Above all, the class of small free owners had not yet disappeared, on which the king’s authority could reach directly, without being dispersed in passing through infinite interposed groups, formed on the basis of the benefit, immunity and vassalage, which, above the obedience due to the sovereign, placed the personal bond of fidelity between the employee and his own direct territorial lord. The Church too favored an evolution in the national sense. In this regard, the councils held in Mainz in October 847 and 848 were significant, the first for the decision to also use the German language in the religious instruction of the people, the second for the intervention, as well as of the archbishops of Mainz and of Salzburg with the bishops dependent on them, including the bishops of Münster and Osnabrück, whose archdiocese, Cologne, was then located outside the borders of the kingdom. Ludovico il Germanico endeavored to help the tendencies towards a greater union of his peoples, and these generally showed themselves obsequious; but he could not escape the ancient custom of dividing states among children, with the consequent rivalries which, in view of the division or the division completed, were the cause of continuous internal struggles. And three were the revolts of the sons of Ludovico il Germanico, but they were not as serious as those of the sons of Ludovico il Pio. Carlomanno, who ruled the Eastern March (861-862), began; followed (866) Louis the Younger, dissatisfied with the division established in 865; finally (871) it was the turn of Charles the Fat, who together with Ludovico the Younger rebelled against a new division, which favored Carlomanno too much, following the enlargement of the states of Louis the German for the treaty of Mersen. But always, rapid conciliations prevented the disagreements from becoming incurable. The division of 865 constituted the substantial basis of the definitive order, for which three kingdoms were formed: of Bavaria, with the Eastern March, Carinthia and the high sovereignty over the Slavs of Moravia and Pannonia, under Carlomanno; of Saxony, with Franconia and Thuringia, under Louis the Younger; of Alamannia, under Charles the Fat. In 873 Ludovico il Germanico decided to let his sons effectively rule their kingdoms, reserving himself to intervene with his decisions only in serious cases. As can be seen, evolution in the national sense took a serious blow, and Germany was brought back to the autonomy of its ancient major ethnic groupings. On the eastern border, the struggle against the Slavs continued, with victorious campaigns north of the Elbe against the Abodrites (844, 862) and less fortunes in the south-east, where it was not possible to stop the growing power of the Moravians. Louis the German overthrew their leader Mojmir, and replaced him with his nephew, Rostislavo (846). But, even he rebelled, only in 870 the betrayal of his nephew, Svatopluk (Sventiboldo), allowed his capture. Placed at the head of the Moravians, Svatopluk in turn rebelled and defeated the Bavarians of Charlemagne (871 and 872). Then Louis the German was forced, in 874, to recognize Svatopluk as prince of his Slavs, with no other obligations than a slight tribute. Svatopluk (Sventiboldo), allowed its capture. Placed at the head of the Moravians, Svatopluk in turn rebelled and defeated the Bavarians of Charlemagne (871 and 872). Then Louis the German was forced, in 874, to recognize Svatopluk as prince of his Slavs, with no other obligations than a slight tribute. Svatopluk (Sventiboldo), allowed its capture. Placed at the head of the Moravians, Svatopluk in turn rebelled and defeated the Bavarians of Charlemagne (871 and 872). Then Louis the German was forced, in 874, to recognize Svatopluk as prince of his Slavs, with no other obligations than a slight tribute.
The following year, the death of Emperor Ludwig II (12 August 875) suddenly brought the Italian and imperial question to the fore in the politics of the young German kingdoms, and renewed the antagonism of the German branch with the French branch of the Carolingians.. Ludovico il Germanico disputed the succession to the Empire and Italy to his half-brother Charles the Bald, and together with his son Ludovico the Younger invaded France, while his other sons, who went down to the peninsula, tried, unsuccessfully, to prevent his uncle from taking the two crowns. But death interrupted the action of Louis the German (Frankfurt am Main, 28 August 876). Charles the Bald then set out to conquer the Rhenish Lotharingia. On the field of Andernach a battle was fought which, with the victory of Louis the Younger, saved the independence of Germany (8 October 876). The French threat led the three brothers to settle against their uncle. But in a decade the protagonists went down to the tomb, disappearing one after the other from the scene: on 6 October 877, Charles the Bald, emperor, king of France and king of Italy; on z2 September 880, Carlomanno, king of Bavaria, who in Italy had been able to be proclaimed king in Pavia (887), but did not obtain the imperial crown; January 20, 882, Ludovico the Younger. Charles the Fat survived for a short time, in which the various crowns were therefore collected, including that of France, after the deaths of Louis III (882) and Carlomanno (884), nephews of Charles the Bald.
For the last time the empire of Charlemagne was united under a single ruler, who belonged to the German Carolingian branch. But even apart from the personal qualities of Charles the Fat, no man was by now able to contain so much variety of ethnic forces, laboriously developed over the course of the eighth and ninth centuries, and each one inevitably reached out to its own path. And Germany also resumed its independence, when, in November 887 Charles the Fat (who died on January 13 888) was deposed from the Tribur diet, which had become an instrument of these forces, the definitive detachment from the Empire of the various national kingdoms took place.