There was still another possible form of sentence. The Barbarians who overthrew the Roman Empire brought with them an ancestral custom, known as compurgation or, in England, as the Wager of Law, by which a defendant, in either a civil or criminal action, could maintain his title or his innocence by taking an oath and bringing a specified number of men who swore to their belief in its truth. They were known as conjurators or compurgators and were in no sense witnesses; they pretended to no knowledge of the facts but only to their confidence in the veracity of their principal. This crude method of establishing the truth was maintained in all the lands occupied by the Teutonic tribes except in Spain, where the Wisigoths early yielded to the influence of the Roman law. It was eagerly adopted by the clergy, who found in it a convenient means of escaping from the harsher expedients of the ordeal or the wager of battle, so that it acquired the name of canonical purgation.[306] In the thirteenth century, the Inquisition found it used in the trial of heretics and necessarily included it among the resources for doubtful cases, although inquisitorial methods were too thorough to call for its frequent employment.
The Spanish Inquisition naturally inherited compurgation among the other traditions of the institution. When conviction could not be had by evidence or torture, and yet the suspicion was too grave to justify acquittal, it could sentence the accused to undergo compurgation. He could not demand it, nor could he decline it, though he might appeal from the sentence; and failure in compurgation was equivalent to conviction, while success was not acquittal but required abjuration and penance at the discretion of the tribunal, because, although legally shown not to be a heretic, the accused had to be punished for "suspicion."