St. Louis,_ by M. Felix
Faure, t. i. p. 388.)

Nevertheless there was no lack of opportunities for interfering with a
powerful arm amongst the sovereigns his neighbors, and for working their
disagreements to the profit of his ambition, had ambition guided his
conduct. The great struggle between the Empire and the Papacy, in the
persons of Frederick II., Emperor of Germany, and the two popes, Gregory
IX. and Innocent IV., was causing violent agitation in Christendom, the
two powers setting no bounds to their aspirations of getting the dominion
one over the other, and of disposing one of the other's fate. Scarcely
had Louis reached his majority when, in 1237, he tried his influence with
both sovereigns to induce them to restore peace to the Christian world.
He failed; and thenceforth he preserved a scrupulous neutrality towards
each. The principles of international law, especially in respect of a
government's interference in the contests of its neighbors, whether
princes or peoples, were not, in the thirteenth century, systematically
discussed and defined as they are nowadays with us; but the good sense
and the moral sense of St. Louis caused him to adopt, on this point, the
proper course, and no temptation, not even that of satisfying his fervent
piety, drew him into any departure from it. Distant or friendly, by
turns, towards the two adversaries, according as they tried to intimidate
him or win him over to them, his permanent care was to get neither the
State nor the Church of France involved in the struggle between the
priesthood and the empire, and to maintain the dignity of his crown and
the liberties of his subjects, whilst employing his influence to make
prevalent throughout Christendom a policy of justice and peace.

That was the policy required, in the thirteenth century more than ever,
by the most urgent interests of entire Christendom.

She was at grips with two most formidable foes and perils. Through the
crusades she had, from the end of the eleventh century, become engaged in
a deadly struggle against the Mussulmans in Asia; and in the height of
this struggle, and from the heart of this same Asia, there spread,
towards the middle of the thirteenth century, over Eastern Europe, in
Russia, Poland, Hungary, Bohemia, and Germany, a barbarous and very
nearly pagan people, the Mongol Tartars, sweeping onward like an
inundation of blood, ravaging and threatening with complete destruction
all the dominions