In the early days of duelling, the weapons of choice were weapons like swords, spears etc. and a stronger man generally had a huge advantage over a weaker one, which many bullies used to their advantage. The introduction of duelling pistols in the 17th century became a huge equalizer for weaker individuals, since they didn't need to rely on physical strength as much.
Gunsmiths were employed to build weapons that were accurate and deadly, but also reliable. Purpose built dueling pistols were manufactured for gentlemen and London became the center for the finest dueling pistol manufacturers - Manton, Durs Egg, Purdey, Nock, Wogdon & Barton etc. Robert Wogdon was already known in England for the quality of his dueling pistols, even before he went into partnership with John Barton. In fact, duels in England were sometimes referred to as "Wogdon affairs". Other fine dueling pistols were also manufactured in France and Germany.
Dueling pistols were traditionally single-shot muzzle loading weapons using flintlock firing mechanisms (and later, percussion lock mechanisms) and fired a ball-shaped bullet made of lead. They were sold in pairs that were matched as closely as possible and usually came in an elaborate case, complete with a variety of cleaning tools and a bullet mold. Caliber was fairly large with 11 mm. (0.45 inch) being one of the more common types, which meant that these bullets carried a lot of punch to them.
Traditional flintlock weapons have a noticeable delay between when the trigger is pulled and when the bullet is discharged. In order to make the delay as short as possible, while still retaining reliability against misfires, dueling pistols would often feature platinum touch holes and light triggers. While hair triggers were unofficially looked at as unsporting, quite a few people had modified their weapons to have extremely light trigger actions. Joseph Manton, the founder of the famous Manton firm, observed several duels and noticed that the firing of the large caliber pistol produced a kick that forced the forearm of the user to bend upwards at the elbow. His solution was to increase the weight of the front of the barrel to counter this kick and therefore made his dueling pistols more accurate. The weight of the pistols were much lighter than average to facilitate faster aiming and the barrels were blued or browned to reduce glare and make aiming easier.
Rifling in the barrels was considered unsporting and officially frowned upon. However, certain manufacturers, such as Manton were known for making pistols with very hard-to-detect rifling grooves for that extra edge in a duel. Similarly, sights were also originally frowned upon, but gradually became acceptable to have.
Dueling slowly faded out by the mid 1850s or so, replaced by boxing as a method of settling arguments, which led to the decline of manufacture of such pistols. However, the pistols themselves still managed to make it to the early 20th century, when Dueling Pistols was an event in the 1912 Olympic games!