A duel is an arranged engagement in combat between two people, with matched weapons, in accordance with agreed-upon rules.
On occasion, duels with pistols or swords were fought between women.
From the early 17th century, duels became illegal in the countries where they were practiced.
In Western society, the formal concept of a duel developed out of the medieval judicial duel and older pre-Christian practices such as the Viking Age holmgang.
In Medieval society, judicial duels were fought by knights and squires to end various disputes.
These type of duels soon evolved into the more chivalric pas d'armes, or "passage of arms", a type of chivalric hastilude that evolved in the late 14th century and remained popular through the 15th century.
A knight or group of knights (tenans or "holders") would stake out a travelled spot, such as a bridge or city gate, and let it be known that any other knight who wished to pass (venans or "comers") must first fight, or be disgraced.
The duel lasted until the other party was too weak to fight back.
In early cases, the defeated party was then executed.
Depiction of a judicial combat in the Dresden codex of the Sachsenspiegel (early to mid-14th century), illustrating the provision that the two combatants must "share the sun", i.e.
align themselves perpendicular to the Sun so that neither has an advantage.
The word duel comes from the Latin 'duellum', cognate with 'bellum', meaning 'war'.