other, because neither is
subject to the other, there must be a third of ampler jurisdiction, to
control both by the ambit of his power.'[18] Such ampler jurisdiction,
which might indeed be claimed for the emperor, but which he had never
the power to exercise, was both claimed and exercised by the papacy. The
papacy, which sought to enforce the Christian canon of conduct in every
reach of life and every sphere of activity, would never admit that
disputes between sovereign princes lay outside the rule of that canon.
Innocent III, in a letter to the French bishops defending his claim to
arbitrate between France and England, stands very far from any such
admission. 'It belongs to our office', he argues, 'to correct all
Christian men for every mortal sin, and if they despise correction, to
coerce them by ecclesiastical censure. And if any shall say, that kings
must be treated in one way, and other men in another, we appeal in
answer to the law of God, wherein it is written, "Ye shall judge the
great as the small, and there shall be no acceptance of persons among
you." But if it is ours to proceed against criminal sin, we are
especially bound so to do when we find a sin against peace.'[19] Here,
in these words of Innocent, the clerical claim to control of peace and
war touches its highest point. In the name of a Christian principle,
permeating all things, and reducing all things to unity, the dread
arbitrament of war is itself to be submitted to a higher and finer
arbitration. The claim was too high to be sustained or translated into
effect. It is not too high to be admired.

Nor was it altogether remote from the actual life of the day. Even to
the laity of the Middle Ages, war was not a mere conflict of powers, in
which the strongest power must necessarily prevail. It was a conflict of
rights before a watching God of battles, in which the greatest right
could be trusted to emerge victorious. War between States was analogous
to the ordeal of battle between individuals: it was a legal way of
testing rights. Now ordeal by battle was a mode of procedure in courts
of law, and a mode of procedure whose conduct and control belonged to
the clergy. If, therefore, war between States is analogous to ordeal, it
follows, first, that it is a legal procedure which needs a high court
for its interpretation (and what court could be more competent than the
papal curia?), and, next, that it is a matter which in its nature
touches the clergy.