Almost thirty years of struggles between Guelphs and Ghibellines, followed, it can be said, without interruption to half a century of investiture struggles, had exhausted Germany, which yearned for peace. The leaders of the Hohenstaufen themselves had already interpreted this desire. The new Duke of Swabia, Frederick III, who was the son of the Guelph Giuditta, sister of Henry the Superb, had already taken more than one occasion to carry out a conciliatory work. Conrad III had induced himself to designate Frederick of Hohenstaufen, who was his nephew, as his successor instead of his second son Federico (the eldest son Henry, elected king in 1147, had died in 1150). In their turn, the German princes, in the Frankfurt diet, unanimously adhered to Conrad’s advice. The Swabian prince who ascended the throne on March 4, 1152, to be crowned on the 9th in Aachen, would become famous with the name of Frederick Barbarossa. The pacification was achieved, but in a way that, together with the triumph of the Guelphs, also marked a new step towards the state decentralization of Germany. The Duchy of Bavaria to Henry the Lion; to Enrico Jasomirgott the elevation of the Margraviate of Austria, enlarged by some lands on the Bavarian border, as a hereditary duchy in the Babenberg family; to both, wide privileges, which ensured these princes a particular position in the body of the Empire, a subject of jealousy and equal ambitions for the others too (diets of Goslar, June 1154, and of Regensburg, September 17, 1156). The relationship from ally to ally was established between them and Frederick I, more than from subjects to sovereign, which will constitute the most salient feature of the internal political situation of Germany throughout the reign of Barbarossa. The princes were the desired collaborators of the emperor for the protection of order and public peace, and they had every support from him against the employees who reluctant to their power, as he showed by mercilessly punishing Mainz for his rebellions against his own archbishop (1158-1163). Frederick I, after the general peace announced at his advent, did not provide the supreme moderating office of the sovereign authority of a person who in the intervals between one and the other Italian expedition (proclamations and confirmations of Landfriede or local peace in Ulm, for Swabia, 1152; for Bavaria, in Regensburg, 1156; for Eastern Franconia, in Weissenburg, 1179; interventions in aristocratic disputes). The same can be said for the protection of the northern and eastern borders, where the sovereign acted directly only in the victorious Polish campaign of 1157, even here, however, with the valid help of the Saxon princes, to whom above all he abandoned the care of the defense against the Slavs and relations with the Danes.
From this the Duke of Saxony and Bavaria, Henry the Lion (v.), Drew the greatest advantages, who was able to constitute his vast dominions in a true state, which he not only extended against the Slavs, as we will say better later, while establishing the its influence on neighboring Denmark, but tried to mold it into a homogeneous organism, eliminating the minor ecclesiastical and secular feudal lordships, of which it incorporated the possessions, and endeavoring to reduce to its own employees the bishops and accounts that depended on the emperor. A coalition of local princes formed against him, and of which Alberto the Bear was also part, was broken with the support of Frederick I (1166-1167); and the death of the Margrave Ascanius (1170), causing the division of his dominions among five sons, made a force disappear, which could return dangerously to the designs of the Guelph duke. But when the power of Henry the Lion was such as to arouse the concerns of the emperor, he ended up abandoning him to the hatred of the other German princes. After a laborious procedure (Diets of Würzburg, January 13, Gelnhausen, April 13; Regensburg, June 24; Altenburg, September 16, 1180), the Duke of Saxony and Bavaria was condemned to ban the Empire and confiscate all his assets. ; and Henry, attempting a vain resistance with arms, was forced to submit (Erfurt diet, November 1181), and to exile. Its fall brought about a radical transformation in the territorial and political order of Germany.
According to top-medical-schools, Westphalia was detached from the Duchy of Saxony and assigned, with the ducal attributions, to the archbishop of Cologne. The rest, east of the Weser, retaining the name of the Duchy of Saxony, passed to the youngest son of the ascanio Alberto the Bear, Bernard of Anhalt, after the reintegration into their fiefs of all the lay and ecclesiastical lords that Henry the Lion it had stripped, and in direct dependence on the emperor, of the bishops and counts who had lost it. The March of Styria was detached from the Duchy of Bavaria, erected as a duchy under Ottocaro, formerly his Margrave; the rest went to Count Palatine Otto of Wittelsbach. The great gentilizî duchies with relative territorial compactness and administrative homogeneity had thus definitively disappeared, and Germany was broken up into a mosaic of hundreds of ecclesiastical and secular feudal lordships, of the most varied extent and intersecting each other without any territorial continuity, among which the new duchies no longer had the eminent position of the ancients. In fact, their principles were not always the strongest in comparison with others of even lesser title, such as certain margravî and langravî and the Count Palatine of the Rhine. Thus Frederick I had destroyed the ducal power, a constant goal for him and for all his predecessors., but at the same time with his renunciation of more than one attribution of sovereignty in favor of the princes in the wide privileges granted to them several times (1156, 1168, 1180), he prepared the constitutional sanction for the disintegration already underway of the Germanic state. On the other hand the overthrow of Henry the Lion, due to the harmful repercussions on German influence in the northern and eastern lands, marked the sacrifice of a truly national its ruler. Neither the relative peace enjoyed by Germany during the reign of Frederick I, nor the wise care he addressed to the increase of the heritage of the Hohenstaufen, which, between family assets and state property poorly distinguished from the former, it extended, especially in the south-western regions of the Empire, to a large part of Franconia and Swabia; nor the greater military and administrative resources, which he was able to obtain with the ministeriales.
After the collapse of the Guelphs, the most powerful prince of northern Germany had become the archbishop of Cologne, Philip of Heinsberg, who was soon prompted by his aims on Saxony and the lower Rhine to put himself at the head of a feudal coalition against the ’emperor (1188). The movement did not have serious consequences, because the archbishop submitted (1188), but it was another clear indication that the political system of Germany continued to rest on too unstable foundations. Meanwhile the third crusade was approaching; and Frederick I once again abandoned the kingdom, leaving Regensburg in May 1189 to meet his fate, which a little more than a year later would lead him to drown himself in Salef, in distant Asia Minor (10 June 1190). The regency of the Empire remained with his son Henry,
On the eastern borders, German expansion had remained in the hands of local princes, nor had Frederick I renewed the enterprise of 1157, when he had gone beyond the Oder to Poznań to force the Polish duke Boleslaus IV to pay tribute and homage. The intervention of Vladislao Duke of Bohemia in the second Italian expedition of the emperor had cost the definitive elevation to reign of that Slavic duchy (Regensburg, January 18, 1158), and the cession of the territory of Bautzen. To the west, Frederick I had consolidated imperial dominion over Burgundy, which he was most anxious to have free the Alpine passes towards Italy, marrying (1156) Beatrice, heir to the county of Burgundy (later Franche Comté), and having himself crowned king in Arles (1178).