With the accession of Frederick I the quarrel between Empire and Papacy enters on a new phase. On the death of Henry V the natural candidate of the papal party for the German throne was Henry the Black Duke of Bavaria, the head of the family of Welf or Guelf. But he was old, and related by marriage to the Hohenstaufen. He was, however, bribed to acquiesce in the election of Lothair by the offer of Lothair's daughter and heiress, Gertrude, as a wife for his son Henry the Proud. This marriage determined the whole course of German history. Henry the Proud obtained the duchy of Bavaria from his father and the duchy of Saxony from his father-in-law. Thus, if the Hohenstaufen family were the heirs of the Franconian Emperors, the Guelfs became the representatives of the opposition to that line which had centred in Saxony; and for the old contest between Papacy and Empire, Saxon and Franconian, there was now substituted a dynastic struggle between Weiblingen or Ghibelline and Guelf. The Guelfs were the papal party only in the sense that, like the Saxons, they were in opposition to the dynasty which occupied the German throne and claimed the imperial title. The name, however, was extended to Italy: it was applied to the collective opposition to the imperial power, and therefore came to denote the friends of the Papacy. [Sidenote: Frederick I.] So far the contest had been confined to Germany; for Lothair had sacrificed the claims of the empire to his own immediate interests, while Conrad had never set foot in Italy after his accession to the German throne. But as the attempt of Lothair to crush the acknowledged Ghibelline leaders had been thwarted, so Conrad had failed to render the Guelf harmless; and it was the pretensions of Henry the Lion, the son of Henry the Proud, which determined Conrad to waive the claims of his young son to the succession, and to recommend to the nobles the choice of his nephew Frederick. But Conrad's nomination would have been of little account. Frederick's claims were largely personal. Already before he succeeded his father as Duke of Suabia he had shown a combination of boldness in action with a conciliatory disposition which marked him out as a leader and a statesman. To this was added, as with Conrad, the prestige of a crusader; while in view of the bitter rivalries of the last two reigns, it was a recommendation that Frederick united in his person the two families whose strife had divided the kingdom. Two years elapsed from his accession before Frederick was free to set out for Italy. As the heir of the Franconians his probable attitude was a matter of some anxiety at Rome and in Italy generally. He was no enemy of the Church. His first act after his coronation at Aachen (March 9th, 1152) was to announce his accession to the Pope, who sent him a return message of goodwill. But from the outset Frederick showed his intention of taking a high line, for, in a disputed election at Magdeburg he obtained a party for a