The "Oath of purgation" is a procedure element of the jurisdiction from the early and high Middle Ages. The "Oath of purgation" is imposed upon defendants in order to "clean-wash" themselves. Only if the oath succeeds is the defendant considered innocent, otherwise he is condemned. The success of the "Oath of purgation" could take every now and then very abstruse forms. Thereby the simple slip of the tongue during the repetition of the oath's formula imposed by the court was already a confession.

The methodology of the "Oath of purgation" was based on the conviction that particular celestial powers would let the oath fail in the case of a perjury attempt and immediately intervene. It was also possible that the defendant was not given the right for an "Oath of purgation", i.e. then, if he was caught in the act. In this case the plaintiff was allowed to express an accusation oath, which if succeeded, spoke the defendant automatically guilty.

Sometimes it also occurred that oath aids from the close family had to support the defendant when swearing the Oath of purgation. Strangers, who had no immediate family in proximity and couldn't get an oath aid, had to then undergo a judgment by god, e.g. walking over glowing coals, or carrying a glowing horse shoe, where no brand was allowed to show. In the late middle Ages the judgments by god disappeared more and more under influence of the church, which had been taken over out of the time of heathen.

Toward the end of the Middle Ages the "Oath of purgation" slowly loses its meaning. in its place steps the conviction of the defendant by the statement of two reliable witnesses, the so-called "proving". Although preferred was the immediate confession of the accused, the so-called "Urgicht". It became problematic, if there was neither a confession, nor a "proving" even though an "urgent suspicion" existed. Since the defendant could not be condemned without a confession, the last consequence was that the confession "was forced!"  This took place by means of the so-called "embarrassing questioning", meaning torture! The "embarrassing questioning" had to orient itself to an exact specified question catalog, in order not to hurt the process order. If the accused did not admit his guilt after the "embarrassing questioning", he had to be released as "innocent". Thereupon the defendant had to render the so-called "Urfehde", i.e. the promise that he would not set out to revenge himself for the rightfully caused treatment towards his person.

Problem: Particularly for rich and powerful individuals, primarily the aristocracy, it was easily possible to "clean-wash oneself" with the "Oath of purgation", since they always succeeded to get a sufficient number of witnesses to rise before court and prove their innocence.

Source - Wikipedia, the free encyclopedia.