[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 recognized instrumentality in the prosecution of heresy, and the next year he repeated Innocent's emphatic order to the Inquisitors to enforce the insertion of his legislation and that of his predecessors upon the statute books everywhere, with the free use of excommunication and interdict."[1]
A little later, Nicholas IV, who during his short pontificate (1288-1292), greatly favored the Inquisition in its work, re-enacted the bulls of Innocent IV and Clement IV, and ordered the enforcement of the laws of Frederic II, lest, perchance, they might fall into desuetude.[1]
[1] _Registers_, published by Langlois, no. 4253.
It is therefore proved beyond question that the Church, in the person of the Popes, used every means at her disposal, especially excommunication, to compel the State to enforce the infliction of the death penalty upon heretics. This excommunication, moreover, was all the more dreaded, because, according to the canons, the one excommunicated, unless absolved front the censure, was regarded as a heretic himself within a year's time, and was liable therefore to the death penalty.[1] The princes of the day, therefore, had no other way of escaping this penalty, except by faithfully carrying out the sentence of the Church.
[1] Alexander IV decreed this penalty against the contumacious. Sexto, _De Hæreticis_, cap. vii. Boniface VIII extended it to those princes and magistrates who did not enforce the sentences of the Inquisition. Sexto, _De Hæreticis_, cap. xviii in Eymeric, 2a pars, p. 110.
The Church is also responsible for having introduced torture into the proceedings of the Inquisition. This cruel practice was introduced by Innocent IV in 1252.