THE  DECLINE   OF  THE   PAPACY	213
quarrelled with it almost as soon as he had mounted the throne
of the Empire.   The interpretation of the Concordat of Worms
was open to doubt, and Frederick claimed that he was justified
in intervening to fill a vacancy in the archbishopric of Magde-
burg.    Two candidates were put-forward by the Church, each
supported by a strong faction which refused to consider the
rival candidate, and when a deadlock occurred, the Emperor
presented  his  own  nominee.    Both  parties  accepted  the
newcomer, and Frederick promptly treated him as the duly
appointed archbishop, despite the complaints of the papacy.
Shortly afterwards Frederick marched into Italy for the double
purpose of quelling rebellion against the Empire which had
broken out among the Lombards and of receiving the iron
crown from the Pope.    The Emperor did not meet the Pope
(Hadrian IV) until 1155, and then Frederick withheld the
homage which, the Pope insisted, had always been paid by
the secular princes to the supreme spiritual ruler.    That
particular tussle was won by the papacy.    Hadrian was
encouraged by his success, and he demanded that Barbarossa
—now back in Germany—should in effect acknowledge that
he held the Empire as the fief of the Church.    The Pope also
commanded the Emperor to take action against Sicily, which
was in dispute with  both the  papacy and  the Empire.
Frederick ignored both injunctions from the Holy See.
Hadrian therefore negotiated an independent agreement with
Sicily and turned that kingdom into his ally, although it was
still the enemy of Barbarossa, and gave papal support to the
Lombards, who were again in rebellion against the Empire.
Frederick was threatened with excommunication if he did not
come to terms with the insurgents.
Hadrian died in 1159 before putting this threat into
practice, and two candidates claimed the See of St. Peter's—
Roland (Alexander III), who supported Hadrian's policy of
an alliance with Sicily and the Lombards against Barbarossa j
and Octavian, who favoured peace with the Emperor.