What can be said about the relative severity or leniency of inquisitorial justice? What was the outcome in the thousands of trials recorded in the appendices to this essay? Despite popular notion’s to the contrary, only a very small percentage of cases concluded with capital punishment. Canon law prescribed that only the obstinate and unrepentant who refused to be reconciled to the church, those who had suffered previous convictions for formal heresy, or those who were convicted of especially heinous crimes were liable to the death penalty.
The available figures on the numbers of those handed over by the Inquisition to the secular arm suggest that the executed were relatively few. Only four of the first thousand defendants who appeared before the tribunal of Aquileia-Concordia (1551-1647) were put to death. A tentative calculation for Venice has counted 14 executions between 1553 and 1588, plus 4 deaths occurring in prison and 4 extraditions to deaths in Rome between 1555 and 1593. Only 12 executions for heresy have been counted for Malon during the second half of the 16th century (but on the basis of incomplete documentation), and only one, in 1567, for the religious heresy in Modena; and of the more than two hundred sentences (several involving more than one defendant) contained in the Trinity College manuscripts mentioned above, for parts of the years 1580-1582, only four called for condemnations to the stake.
In his studies of the Friuli witchcraft trials, Carlo Ginzburg encountered neither the use of torture in the proceedings nor a single execution; in fact, only rarely was a case brought to a conclusion. The names of 97 victims of the Holy Office in the city of Rome for the period 1542-1761 have been extracted from the records of the archconfraternity, whose function it was to accompany the condemned to their deaths. As for Spanish inquisitorial courts, they executed approximately 820 people between roughly 1540 and 1700, out of a total of more than 44,000 cases, for a rate of 1.9 percent.
John Tedeschi, The Prosecution of Heresy (1991)