e of their Bishops, to execute fully and
conscientiously the ecclesiastical and civil laws against heresy. If
they refused or neglected to do this, they themselves were liable to
excommunication and their rebellious cities to interdict.[1]

[1] Decretal _Ad abolendam_, in the Decretals, cap. ix, _De
Haereticis_, lib. v, tit. vii. Cf. Sexto, lib. v, tit. ii, c. 2. _Ut
Officium_; Council of Arles, 1254, can. iii; Council of Beziers,
1246, can. ix.

Innocent IV, in 1252, enacted a law still more severe, insisting on
the infliction of the death penalty upon heretics. "When," he says,
"heretics condemned by the Bishop, his Vicar, or the Inquisitors,
have been abandoned to the secular arm, the podesta or ruler of the
city must take charge of them at once, and within five days enforce
the laws against them."[1]

[1] Eymeric, _Directorium_, Appendix. p. 8.

This law, or rather the bull _Ad Extirpanda_, which contains it, was
to be inscribed in perpetuity in all the local statute books. Any
attempt to modify it was a crime, which condemned the offender to
perpetual infamy, and a fine enforced by the ban. Moreover, each
podesta, at the beginning and end of his term, was required to have
this bull read in all places designated by the Bishop and the
Inquisitors, and to erase from the statute books all laws to the
contrary.

At the same time, Innocent IV issued instructions to the Inquisitors
of upper Italy, urging them to have this bull and the edicts of
Frederic II inserted in the statutes of the various cities.[1] And to
prevent mistakes being made as to which imperial edicts he wished
enforced, he repeated these instructions in 1254, and inserted in one
of his bulls the cruel laws of Frederic II, viz., the edict of
Ravenna, _Commissis nobis_, which decreed the death of obdurate
heretics; and the Sicilian law, _Inconsutilem tunicam_, which
expressly decreed that such heretics be sent to the stake.

[1] Cf. the bulls _Cum adversus, Tunc potissime, Ex Commissis nobis_,
etc., in Eymeric, ibid., pp. 9-12.

These decrees remained the law as long as the Inquisition lasted. The
bull _Ad Extirpanda_ was, however, slightly modified from time to
time. "In 1265, Clement IV again went over it, carefully making some
changes, principally in adding the word 'Inquisitors' in passages
where Innocent had only designated the Bishops and Friars, thus,
showing that the Inquisition had, during the interval, established
itself as the recogniz