|The dueling area was typically|
60 feet square.
One of the things "everyone knows" about the Middle Ages is the idea of Trial by Combat: the act of fighting to determine who is right in a dispute. It was a custom followed primarily by Germanic culture; it was later brought to Great Britain.* It was recognized as a valid part of German tribal law as far back as the early 8th century in the Lex Alamannorum [Latin: "Law of the Alemanni"; the Alemanni were a Germanic tribe on the Upper Rhine].
The Fourth Lateran Council of 1215, in an effort to tamp down this sanctioned violence, tried to ban Trial by Combat in favor of Trial by Jury. "Judicial duels"—that is, a fight sanctioned by the local legal system—were too unpredictable a measure of justice. German countries kept up the practice, however. The 15th century fencing master, Hans Talhoffer, detailed the ways in which judicial duels could be carried out, and listed seven offenses that merited such a trial: murder, treason, desertion of your lord, unlawful captivity, heresy, perjury, rape.
Commoners were required to take their dispute to court first in order to have Trial by Combat sanctioned by the local legal system. Nobility, however, could take it upon themselves to duel over a dispute, leading to the "gentleman's duel" of later years. The combatants would each bring a "second" to help arrange the particulars, everything from the location to making sure the horses are saddled properly. Sometimes these seconds would meet separately to discuss a more peaceful solution that the combatants could not discus face to face due to their pride.
The combatants had some duties, too, besides fighting. They would attend (separate) church services prior to combat, and make a donation to the church. They had to be ready to begin the combat by noon, and it had to be concluded by sundown.
The last official judicial duel is unknown, but we know that King Charles I of England intervened to prevent a couple, one in 1631 and one in 1638. In 1818, Abraham Thornton, already acquitted of the murder and rape of Mary Ashford, had an accusation brought by Mary's brother, William. Thornton claimed the right to Trial by Combat; the court decided that he was justified, since the "evidence" for his guilt was circumstantial and disputable, and because Parliament had never removed the right to Trial by Combat from the books. Ashford backed down. The following year, Parliament abolished Trial by Combat.
*It is not to be confused with Trial by Ordeal which involved causing an accused to suffer some ordeal that would "prove" his guilt or innocence.