In October 1189 Henry the Lion reappeared in northern Germany, determined to reconquer the lost dominions, and the following year, the discontent of the Lorraine princes and many German lords due to the suspicion that Henry VI had been the instigator in the murder of their candidate for the episcopal see of Liège, he determined against him a powerful coalition, in which the archbishop of Mainz, the Langravî of Thuringia and Misnia, the Zähringen, and who joined the Guelphs predominated. From abroad they helped England, Denmark, and south of the Alps the national party, which supported Tancred of Lecce against the emperor. The capture of the King of England, Richard the Lionheart, while returning from the crusade, by Leopold V of Babenberg, Duke of Austria, and his delivery (1193) to Henry VI suddenly changed a situation, which for the emperor threatened to become desperate. To prevent the English king from being handed over to his brother Giovanni Senzaterra and the king of France Philip Augustus, his most terrible enemies, the coalition renounced his plans, and thus obtained his release (1194). On 6 August 1195 Henry the Lion ended his troubled life in Brünswick, his only possession with Lüneburg; and the following year a large part of the princes allowed the emperor to snatch consent to his constitutional reform plan from the Würzburg diet, which aimed to make the crown hereditary in the Hohenstaufen family. The plan was not followed up, because it ran into an irreducible opposition to the diet of Erfurt, under the impulse of the Landgrave of Thuringia (October 1196), while Henry VI was in Italy. The emperor did not insist. At his own request, his son Frederick was elected king in Frankfurt (December 1196) according to the usual procedure. The disappearance of Henry VI, who died in Sicily on 28 September 1197, after a reign in which he had mainly dealt with Italy, left Germany in a precarious situation and on the eve of another very serious crisis.
According to Localcollegeexplorer,Frederick II was not yet three years old; the same supporters of the Hohenstaufen considered it necessary, in order to save the throne to the family, to elect his uncle Philip Duke of Swabia as king (Mühlhausen near Erfurt, 6-8 March 1198). A few months later the opposing party, led by the archbishop of Cologne, Adolfo dei conti di Berg, still met with the Guelphs, proclaiming king (9 June) one of the sons of Henry the Lion, Otto of Brunswick, who on 12 July 1198 took the crown in Aachen. Germany had three kings, and was once again torn apart by the struggle between Guelphs and Ghibellines. The Guelphs had their adherents especially in northwestern Germany, in the lower Rhine region and in Westphalia, and scarce resources came to Otto IV from his not rich possessions in Brünswick-Lüneburg; but he had an ally with England. On the other hand, the to have among its proponents Lorraine princes, such as Count Baldwin V (VIII), who was both a vassal of the Empire as Count of Hainault, and reluctant to vassalize the King of France, as Count of Flanders, and the alliance with the England, made the situation of Lower Lorraine particularly delicate, due to the intertwining of British and French interests with German ones in that region, and the insertion of the duel between France and England in the internal struggles of Germany. This must have proved fatal to the Guelphs. In Rhenish Franconia, Otto IV stood for his brother Henry, Count Palatine of the Rhine; in eastern Saxony he was partly with the Guelphs, partly with the Swabians, the Margrave of Thuringia. Stronger appeared the Hohenstaufen, ministeriales, on the rich heritage, on the great traditions of the family. But the intervention of Pope Innocent III weighed above all in the fate of the conflict. Having declared himself in favor of Otto IV (1201), if at first it seemed to balance the arrogance of the Hohenstaufen, actually determined a general reaction in their favor, due to the discontent aroused by the papacy’s interference in the internal affairs of Germany. The German episcopate almost entirely solidified itself with the Hohenstaufen, while the partisans of the Guelphs dwindled. Otto IV himself suffered a serious defeat at Wassenberg (1206). But the situation was reversed by the assassination of Philip (21 June 1208). The general weariness of Germany led the Swabian party to an understanding with Otto IV, who was again elected king, also recognized by his opponents, in Frankfurt (11 November), where general peace was proclaimed. His engagement to Philip’s ten-year-old daughter, Beatrice, was to seal the reconciliation. On 4 October 1209 he could also take the imperial crown in Rome. It was a brief respite. When the return of Otto IV to the traditional imperial politics in Italy contrary to the interests of the Church induced Innocent III to put forward the protégé Frederick of Swabia, the party of the Hohenstaufen, which saw in him the legitimate successor to the throne, a powerful resource. In September 1211 Leopold VI of Babenberg, Duke of Austria, Louis I of Wittelsbach, Duke of Bavaria, King Ottokar of Bohemia promoted, in the Nuremberg diet, the offering of the crown to the young man, who rushed to Germany. The civil war parched; on 18-19 November 1212 Frederick II made an agreement with Philip Augustus in Vaucouleurs, on 5 December he was elected, in Frankfurt, on the 9th crowned king, in Mainz. Two years later the fortune of the Guelphs set forever on the fields of Bouvines, where the militias of the French king routed those of Otto IV, Giovanni Senzaterra, and their feudal allies of Flanders (July 27, 1214). On 5 July 1215, Frederick II was again crowned king in Aachen; his rival, after having supported himself for some time in Eastern Saxony, died in Harzburg (May 19, 1218).