German king and Roman emperor, b. at Argentau (Dept. of Orne), c. 1182; d. 19 May, 1218; son of Henry the Lion and of his wife Mathilda, daughter of King Henry II of England and sister of Richard Coeur de Lion. In the latter, by whom he was made Earl of March, Otto found a constant support. This connexion of the Guelphs with England encouraged Adolf of Cologne, upon the death of Henry VI and the election of Philip of Swabia by the Hohenstaufens, to proclaim Otto king, which took place in Cologne, on 9 June, 1198. The next aim of Otto was to obtain the confirmation of his position as head of the kingdom. The power of the Hohenstaufens was, however, too great. Otto and his followers hoped that Pope Innocent III, who was hostile to the Hohenstaufens, would espouse Otto's cause in the contest for the German throne. Innocent awaited developments. To him the individual was of little importance, his chief solicitude being for the recognition of the right to decide contested elections to the German throne, and, in consequence, his suzerainty over kingdom and empire. The year 1200 was favourable to Philip. He, however, made the mistake of taking possession of the episcopal See of Mainz in defiance of canonical regulations, whereupon Innocent declared for Otto. The year 1201 marked the beginning of energetic action on the part of the Curia in Otto's behalf. While the papal legate, Guido of Palestrina, constantly gained new friends to Otto's cause, the "sweet youth" (süsse junge Mann), as Walther von der Vogelweide calls Philip, remained inactive, protesting the while at the attitude of the pope. When, in 1203, Thuringia and Bohemia also deserted him, Philip's affairs were nearly hopeless. Otto had made the broadest concessions to the Holy See, wishing "to become King of the Romans through the favour of God and the pope". He confirmed the papacy in its secular possessions, relinquished the property of Mathilda of Tuscany, and even guaranteed to the pope the revenues of Sicily. He resigned all claims to dominion in Italy, promising to treat with the Romans and with the cities of Italy only in concurrence with the pope. The purpose of Innocent to become the overlord of Italy was thus all but accomplished. The moral results of this great contest for the throne were unfortunate. Princes and bishops shamelessly changed their party allegiance.

In 1204 the scale turned in Philip's favour. This was due to the fact that the whole north-western part of the kingdom became involved in the war for the succession in Holland, and could therefore manifest but little interest in the affairs of the Guelphs. The year 1205 saw a general desertion from Otto's cause, his dominion being finally limited to the city of Cologne and his possessions in Brunswick. The Archbishop of Cologne, Adolf, had also gone over to Philip's standard, upon which sentence of excommunication had been pronounced against him. The Diocese of Cologne was then subjected to all the confusion of a schism. In addition the city of Cologne finally fell into the hands of the Hohenstaufens. Without further delay, the pope withdrew his support from the apparently lost cause of the Guelphs, and began negotiations with the Hohenstaufens, in which he was joined by the other cities of Italy. After mutual concessions, the pope promised to acknowledge Philip and to crown him emperor. When about to deal the last crushing blow to the Guelphs, Philip was murdered by the Count Palatine Otto von Wittelsbach at Bamberg, on 21 June, 1208. The princes now rallied round Otto, who had shown his recognition of their right of election by coming forward once more as a candidate for the crown. Otto's next step was to take as his wife the daughter of his murdered enemy, which was an added incentive to the Hohenstaufens to yield themselves to his sway. On 11 November, 1208, he was once more elected, this time at Frankfort, which event was followed by a period of mutual understanding and a short term of peace for the kingdom. To ensure the support of the pope, Otto drew up a charter at Speyer on 22 March, 1209, in which he renewed the concessions previously made, and added others. He now promised not to prevent appeals regarding ecclesiastical affairs being made to the Holy See. Of the greatest significance was his act acknowledging the exclusive right of election of the cathedral chapter. In 1209 Otto journeyed to Rome to receive the imperial crown. On this occasion he did not come as a humble petitioner, but as German king to order the affairs of Italy and to bring about the re-establishment of its relations with his kingdom. As soon as the coronation was an accomplished fact (4 Oct., 1209), it was apparent that he intended to make the policy of the Hohenstaufens his own. His first step was to lay claim to Sicily. The pope, who must have feared a re-establishment of the dominion of Henry VI in lower Italy, excommunicated Otto on 18 October, 1210, and determined to place the young Hohenstaufen, Frederick II, upon the throne. The latter secured the support of France, and thus succeeded once more in winning the German princes to his cause. On the death of Otto's wife, a Hohenstaufen princess, the Hohenstaufen party completely abandoned his standard for that of Frederick. The renewed conflict between the Guelphs and the Hohenstaufens was not decided in Germany, but abroad. Conditions in the kingdom were so changed that foreign arms were destined to decide the contest for the German crown. So crushing was the defeat inflicted upon the Guelph and English forces by Philip Augustus at Bouvines (27 July, 1214), that Otto's cause was lost. Although he endeavoured in 1217 and 1218 to make a further effort to secure the throne, he met with no great success. Absolved from his excommunication, he died on 19 May, 1218, and was buried at St. Blasien in Brunswick.

LANGERFELDT, Kaiser Otto IV der Welfe (Hanover, 1872); WINKELMANN, Philipp von Schwaben und Otto IV von Braunschweig (2 vols., Leipzig, 1873-78); HURTER, Geschichte Papst Innocenz III und seiner Zeitgenossen (4 vols., Hamburg, 1834-72); GROTEFEND, Zur Charakteristik Philipps von Schwaben und Ottos IV von Braunschweig (Jena, 1886); SCHWEMER, Innocenz III und die deutsche Kirche während des Thronstreites von 1198-1208 (Strasburg, 1882); LUCHAIRE, Innocent III (1904).

F. Kampers.