It may not be an exaggeration to claim, in fact, that in several respects the Holy Office [of the Inquisition] was a pioneer in judicial reform.
The defense attorney was an integral part of Roman trial procedure at a time when he played only a ceremonial role in the great imperial legal code, the Constitutio Criminalis Carolina (1532) and was being deliberately excluded by the French Ordinance of Villers-Cotterets (1539). In England felons were denied the right to counsel until 1836. Whereas in inquisitorial courts the defendant received a notarized copy of the entire trial (with the names of the prosecution witnesses deleted) and was given a reasonable period of time to prepare his reply to the charges, in secular courts the evidence against him was read and he had to make his defense on the spot. Skepticism in regard to witchcraft invaded Roman legal circles at a time when other parts of Europe remained in the grip of a witchhunting mania. Not least among the reasons which spared Italy the epidemics of bloody persecutions which ravaged northern Europe from the late sixteenth through much of the seventeenth century, was the insistence by the Inquisition that the testimony of a suspected witch was of extremely limited validity as a basis for prosecution against others. Judges were instructed, for example, to discount testimony of a witch against persons whom she named as participants at Sabbats since it was assumed that frequently they were transported to these nocturnal reunions not physically but in illusions inspired by the Devil.
And, if it is true, as John Langbein asserts in his book, Prosecuting Crime in the Renaissance, that the beginning of imprisonment for punishment, rather than for the purpose of custody during the trial, can be traced back on the continent only to the closing decades of the sixteenth century, then the Inquisition, through its centuries-long practice of incarcerating ad poenam, must be regarded also as a pioneer in the field of penology, at a time when secular judges, in pronouncing sentence, had as alternatives only the stake, mutilation, the galleys, and banishment.
John Tedeschi, The Prosecution of Heresy (1991)