The Supplementary Oath in Medieval Canon Law

The institution of the oath was applied in a historical form as well as at present in several contemporary legal systems creatively developed by canonists while practically applying the so-called Roman-Canonical procedure. From the chronological point of view, the most important was the period of High Middle Ages when it was elaborated in small details and when its types were standardized. The most frequently used were the so-called "supplementary oath" applied principally when the ecclesiastical court had at its disposition partial evidence or the presumption in favour of the party with the burden of evidence existed and it was impossible to meet the requested standard of full canonical proof. The main goal of this article is to point out the character of this type of oath in classical canon law including its practical application, not omitting its conceptual, especially Roman-law bases.