From this time on we find the name _Guelf_ assumed by the party in Italy which was opposed to the emperors.[122] This is but another form of the name of the Welf family, who made most of the trouble for the Hohenstaufens in Germany. A certain Welf had been made duke of Bavaria by Henry IV (in 1070). His son added to the family estates by marrying a rich north-German heiress. His grandson, Henry the Proud, looked still higher and became the son-in-law of the duke of Saxony and the heir to his great duchy. This, added to his other vast possessions, made him the most powerful and dangerous of the vassals of the Hohenstaufen emperors. [Sidenote: Division of Saxony and the other great German duchies.] On returning from his disastrous campaign against the Lombard towns, Frederick Barbarossa found himself at war with the Guelf leader, Henry the Lion (son of Henry the Proud), who had refused to come to the emperor's aid before the battle of Legnano. Henry was banished, and Frederick divided up the Saxon duchy. His policy was to split up the old duchies, for he clearly saw the danger of permitting his vassals to control districts as large as he himself held. [Sidenote: The Hohenstaufens extend their power into southern Italy.] 70. Before his departure upon the crusading expedition during which he lost his life, Frederick saw his son, Henry VI, crowned king of Italy. Moreover, in order to extend the power of the Hohenstaufens over southern Italy, he arranged a marriage between the young Henry and Constance, the heiress to the Norman kingdom of Naples and Sicily.[123] Thus the hopeless attempt to keep both Germany and Italy under the same head was continued. It brought about new conflicts with the popes, who were the feudal suzerains of Naples and Sicily, and ended in the ruin of the house of Hohenstaufen. [Sidenote: Henry VI, 1190-1197.] [Sidenote: His troubles in Italy and Germany.] Henry VI's short reign was beset with difficulties which he sturdily met and overcame. Henry the Lion, the Guelf leader, having broken the oath he had sworn to Frederick to keep away from Germany, returned and organized a rebellion. So soon as this was quelled and the Guelf party was under control for a time, Henry VI had to hasten south to rescue his Sicilian kingdom. There a certain Norman count, Tancred, was leading a national revolt against the German claimant. The pope, who regarded Sicily as his fief, had freed the emperor's Norman subjects from their oath of fidelity to him. Moreover, Richard the Lion-Hearted of England had landed on his way to the Holy Land and allied himself with Tancred.