"Judicial Duel" a/k/a "trial by combat" was a Germanic way to settle accusations in the absence of a confession or witness. Unlike Martin's books or TV show, the two actual litigants fought each other, one on one. The victor of the fight was judged as the winner of the dispute. This Germanic law appears by reference throughout the Middle Ages in Europe. References to such duels virtually seems to disappear sometime toward the end of the 16th Century. History reveals that some exceptions to the one on one rule have occurred. For example, Louis the Pious required witnesses to fight each other concerning cases involving the clergy. In 2015, the Fourth Lateran Counsel officially discouraged the use of duels to settle disputes. Subsequently, Pope Honorius III requested that the Teuonic order cease the practice altogether. Nevertheless, in the 15th Century, fencing schools in Germany were still training people for such duels. (Was this one of the first law schools?) As of 1459 Thott codex specified that charges including desertion, murder, perjury, rape and treason allowed for trial by combat in the absence of witnesses.
At some point in the 16th Century, a person facing trial by combat was allowed the assistance of a squire (a second.) (This would appear to be analogous to today's "second chair" in a jury trial.) The squire would perform similar work to a "local counsel", arranging negotiations, forums and agreeing to certain equipment or weapons. The courtroom (dueling ground) was typically 60 square feet. The last litigant standing was declared the victor.
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