ent. But when the Emperor Frederic had revived the
legislation of his Christian predecessors of the fourth, fifth, and
sixth centuries,[1] and had made the popular custom of burning
heretics a law of the empire, the Papacy could not resist the current
of his example. The Popes at once ordered the new legislation
vigorously enforced everywhere, especially in Lombardy. This was
simply the logical carrying out of the comparison made by Innocent
III between heresy and treason, and was due chiefly to two Popes:
Gregory IX who established the Inquisition under the Dominicans and
the Franciscans, and Innocent IV who authorized the Inquisitors to
use torture.

[1] Cf. the law of Arcadius of 395 (_Cod. Theodos_., xvi, v. 28).

The theologians and casuists soon began to defend the procedure of
the Inquisition. They seemed absolutely unaffected, in theory at
least, by the most cruel torments. With them the preservation of the
orthodox faith was paramount, and superior to all sentiment. In the
name of Christian charity, St. Thomas, the great light of the
thirteenth century, taught that relapsed heretics, even when
repentant, ought to be put to death without mercy.

How are we to explain this development of the doctrine of the Church
on the suppression of heresy, and granting that a plausible
explanation may be given, how are we to justify it?

. . . . . . . .

Intolerance is natural to man. If, as a matter of fact, men are not
always intolerant in practice, it is only because they are prevented
by conditions born of reason and wisdom. Respect for the opinion of
others supposes a temper of mind which takes years to acquire. It is
a questions whether the average man is capable of it. Intolerance
regarding religious doctrines especially, with the cruelty that
usually accompanies it, has practically been the law of history. From
this viewpoint, the temper of mind of the mediaeval Christians
differed little from that of the pagans of the empire. A Roman of the
second or third century considered blasphemy against the gods a crime
that deserved the greatest torments; a Christian of the eleventh
century felt the same toward the apostates and enemies of the
Catholic faith. This is clearly seen from the treatment accorded the
first Manicheans who came from Bulgaria, and gained some adherents at
Orleans, Montwimer, Soissons, Liege, and Goslar. At once there was a
popular uprising against them, which evidenced what may be called the
ins