Nobles weren't the only ones participating in duels. Some of the earliest legal systems relied on dueling to determine guilt or innocence. Prior to the 11th and 12th centuries, someone accused of a crime would have to go through a trial or ordeal of some kind [ref], and one form of trial was the trial by combat. They might have to face their accuser or a trained dueling expert appointed by the court. Winning a duel was a sign that God favored you, therefore proving innocence.
Many duelists (including nobles) issued challenges for pragmatic reasons, as well. For a man who was confident in his own skill at dueling, it was the solution to virtually any problem. Debts could be erased by finishing off the creditor. Land disputes were settled in a similar manner. Rivals for jobs or political appointments were all potential dueling partners, while elections could be decided with swords or guns rather than votes.
In antebellum Missouri, the political duel became a way of life. According to Dick Steward in "Duels and the Roots of Violence in Missouri," [The duelist's] immediate objective was ... the elimination of a political rival. The duel, therefore, became one upper-class tool in political clashes. From the territorial elections of 1816 through 1824 the code became legitimized as never before or after." In fact, Peter Burnett, the first governor of California, once said of Missouri politics, "It becomes desirable to kill off certain aspirants, to get them out of the way." (Steward, pg. 43).
In the next section, we'll look at the history of dueling.