kish clergy and rescind the divorce; but
it was {192} only in 863 by a council at Rome, where the archbishops of
Cologne and Trier were present, that he was able to proceed to
extremities. He excommunicated those two prelates, and deposed them
with all those who had assisted them: he warned Hincmar of Rheims of
what he had done. The emperor Louis, Chlothochar's brother, marched on
Rome and captured the city; but there, through illness it appears, he
completely submitted to the pope. Nicolas enforced his decision on the
Frankish king, the Frankish bishops, on Hincmar, the great archbishop
of Rheims himself. In a letter he developed the theory that the Empire
owed its confirmation to the authority of the Apostolic See, and that
the sword was conferred on the emperor by the pope, the vicar of S.
Peter. Truly it was said of this pope by one who wrote a century after
his death, "Since the days of Gregory to our own sat no prelate on the
throne of S. Peter to be compared to Nicolas. He tamed kings and
tyrants and ruled the world like a monarch: to holy bishops he was mild
and gentle: to the wicked and unconverted a terror; so that truly may
we say that in him arose a new Elijah."

Of equal though different importance was the action of the papacy in
regard to the East. What is known as the Photian schism is the
divergence between the churches of Constantinople and Rome, which
became critical during the pontificate of Nicolas I.

[Sidenote: The Photian schism.]

Photius, a man of great learning and experience, a scholar and
theologian of the familiar Greek type, was elected Patriarch of
Constantinople on Christmas Day, 857. At the time when Michael III.
determined on his appointment he was not even ordained: in six days he
{193} received the different orders and was made patriarch. But his
election was uncanonical. Ignatius the patriarch, who was still
living, was deposed because of his censures of the emperor's evil life.
Photius announced his election to Pope Nicolas, but Ignatius refused to
surrender his rights; both parties excommunicated each other; and the
emperor mocked at both. But he also asked the pope to send legates to
a council which should restore order to the Church. The Council met in
861. It confirmed Photius in his office, and the papal legates
assented. Nicolas refused to accept the decision and took upon him to
annul it, to depose Photius, to declare the orders conferred by him
invalid, and