The question at issue required a whole change of perspective in regard to crime. It could no longer be viewed as a personal offense between two private individuals but rather as a public crime inimical to the peace and tranquility of the commonweal. Therefore it should be the prerogative of the body politic to investigate, hold trials and punish. This presupposed a centralized government which would organize competent personnel to perform these functions. A very large step was taken by the Church in elaborating the trials by investigation, per inquisitionem, the enquete, in which the pros and cons of the matter were weighed in court and the case decided on the basis of the evidence presented. Originally the Inquisitor relied on the popular clamor, the hue and cry, the notoriety of the individual to bring the person to the official attention of the judge. But with the organization of the inquisitorial tribunal the Inquisitor gradually employed separate officials to investigate offenses, and, to present the evidence in court, the “minister of the Inquisition”.
But a third factor remained as a major stumbling block: what kind of proof would be sufficient for conviction. Legal processes are not born full grown out of the sea like Venus, but rather are the result of a continuous evolution. While the people of the Middle Ages, the Ages of Faith, were quite willing to accept the “judgment of God,” the ordeals, they were hard put to see why another man like themselves should have the superior power of judging them. And so, the determining factor in devising a new rational system of proofs, i.e., one based on objective evidence, was once again the Roman ideal of law. The decision in a criminal case must be based on objective, certain evidence, entirely independent of the will of a judge, which could be subjective and arbitrary. The judge was to be circumscribed by the ancient Roman tradition of complete, full proof, without which an accused could not be convicted of a capital offense. The Roman-canon law of proof governed judicial procedure in capital cases in the High Middle Ages and well into modern times:
1.The testimony of two eye witnesses was sufficient for conviction and constituted full proof.
2. The confession of the accused was accepted as full proof.
3. Circumstantial evidence, however compelling, was insufficient for the conviction in a capital case.
Albert Shannon, The Medieval Inquisition (1991)