The nundinae were the market days which formed a kind of weekend in Rome, Italy, and some other parts of Roman territory. By Roman inclusive counting, they were reckoned as "ninth days" although they actually occurred every eighth day. Because the republican and Julian years were not evenly divisible into eight-day periods, Roman calendars included a column giving every day of the year a nundinal letter from A to H marking its place in the cycle of market days. Each year, the letter used for the markets would shift 25 letters along the cycle. As a day when the city swelled with rural plebeians, they were overseen by the aediles and took on an important role in Roman legislation, which was supposed to be announced for three nundinal weeks (between 17 and 24 days) in advance of its coming to a vote. The patricians and their clients sometimes exploited this fact as a kind of filibuster, since the tribunes of the plebs were required to wait another three-week period if their proposals could not receive a vote before dusk on the day they were introduced. Superstitions arose concerning the bad luck that followed a nundinae on the nones of a month or, later, on the first day of January. Intercalation was supposedly used to avoid such coincidences, even after the Julian reform of the calendar.
The 7-day week began to be observed Italy in the early imperial period, as practitioners and converts to eastern religions introduced Hellenistic and Babylonian astrology, the Jewish Saturday sabbath, and the Christian Lord's Day. The system was originally used for private worship and astrology but had replaced the nundinal week by the time Constantine made Sunday (dies Solis) an official day of rest in AD 321. The hebdomadal week was also reckoned as a cycle of letters from A to G; these were adapted for Christian use as the dominical letters.
In the development of firearms, an important limiting factor was the time it took to reload the weapon after it was fired. While the user was reloading, the weapon was useless, and an adversary might be able to take advantage of the situation and kill or wound the user. Several approaches to the problem of increasing the rate of fire were developed, the earliest being multi-barrelled weapons which allowed two or more shots without reloading. Later weapons featured multiple barrels revolving along a single axis.
The earliest examples of what today is called a revolver were made in Germany in the late 16th century. These weapons featured a single barrel with a revolving cylinder holding the powder and ball. They would soon be made by many European gun-makers, in numerous designs and configurations. However, these weapons were difficult to use, complicated and prohibitively expensive to make, and as such they were not widely distributed.
In 1836, an American, Samuel Colt patented the mechanism that led to the widespread use of the revolver, the mechanically indexing cylinder. According to Samuel Colt, he came up with the idea for the revolver while at sea, inspired by the capstan, which had a ratchet and pawl mechanism on it, a version of which was used in his guns to rotate the cylinder by cocking the hammer. This provided a reliable and repeatable way to index each round and did away with the need to manually rotate the cylinder. Revolvers proliferated largely due to Colt's ability as a salesman. But his influence spread in other ways as well; the build quality of his company's guns became famous, and its armories in America and England trained several seminal generations of toolmakers and other machinists, who had great influence in other manufacturing efforts of the next half century.
Early revolvers were caplocks and loaded as a muzzle-loader: the user poured black powder into each chamber, rammed down a bullet on top of it, then placed percussion caps on the nipple at the rear of each chamber, where the hammer would fall on it. This was similar to loading a traditional single-shot muzzle-loading pistol, except that the powder and shot could be loaded directly into the front of the cylinder rather than having to be loaded down the whole length of the barrel. Importantly, this allowed the barrel itself to be rifled, since the user wasn't required to force the tight fitting bullet down the barrel in order to load it (a traditional muzzle-loading pistol had a smoothbore and relatively loose fitting shot, which allowed easy loading, but gave much less accuracy). When firing the next shot, the user would raise his pistol vertically as he cocked the hammer back so as to let the fragments of the burst percussion cap fall out so as to not jam the mechanism. Some of the most popular cap-and-ball revolvers were the Colt Model 1851 "Navy" Mode, 1860 "Army" Model, and Colt Pocket Percussion revolvers, all of which saw extensive use in the American Civil War. Although American revolvers were the most common, European arms makers were making numerous revolvers by that time as well, many of which found their way into the hands of the American forces, including the single action Lefaucheux and LeMat revolver and the BeaumontAdams and Tranter revolvers, which were early double-action weapons, in spite of being muzzle-loaders.
In 1854, Eugene Lefaucheux introduced the Lefaucheux Model 1854, the first revolver to use self-contained metallic cartridges rather than loose powder, pistol ball, and percussion caps. It is a single-action, pinfire revolver holding six rounds.
On November 17, 1856, Daniel B. Wesson and Horace Smith signed an agreement for the exclusive use of the Rollin White Patent at a rate of 25 cents for every revolver. Smith & Wesson began production late in 1857 and enjoyed years of exclusive production of rear-loading cartridge revolvers in America, due to their association with Rollin White, who held the patent and vigorously defended it against any perceived infringement by other manufacturers (much as Colt had done with his original patent on the revolver). Although White held the patent, other manufacturers were able to sell firearms using the design, provided they were willing to pay royalties.
After White's patent expired in April 1869, a 3rd extension was refused. Other gun-makers were then allowed to produce their own weapons using the rear-loading method, without having to pay a royalty on each gun sold. Early guns were often conversions of earlier cap-and-ball revolvers, modified to accept metallic cartridges loaded from the rear, but later models, such as the Colt Model 1872 "Open Top" and the Smith & Wesson Model 3, were designed from the start as cartridge revolvers.
In 1873, Colt introduced the famous Model 1873, also known as the Single Action Army, the "Colt .45" (not to be confused with Colt made models of the M1911 semi-automatic) or simply, "the Peacemaker", one of the most famous handguns ever made. This popular design, which was a culmination of many of the advances introduced in earlier weapons, fired 6 metallic cartridges and was offered in over 30 different calibers and various barrel lengths. It is still in production, along with numerous clones and lookalikes, and its overall appearance has remained the same since 1873. Although originally made for the United States Army, the Model 1873 was widely distributed and popular with civilians, ranchers, lawmen, and outlaws alike. Its design has influenced countless other revolvers. Colt has discontinued its production twice, but brought it back due to popular demand and continues to make it to this day.
In the U.S. the traditional single-action revolver still reigned supreme until the late 19th century. In Europe, however, arms makers were quick to adopt the double-action trigger. While the US was producing weapons like the Model 1873, the Europeans were building double-action models like the French MAS Modle 1873 and the somewhat later British Enfield Mk I and II revolvers (Britain relied on cartridge conversions of the earlier BeaumontAdams double-action prior to this). Colt's first attempt at a double action revolver to compete with the European manufacturers was the Colt Model 1877, which earned lasting notoriety for its overly complex, expensive and fragile trigger mechanism, which in addition to failing frequently, also had a terrible trigger pull unless given the attentions of a competent gunsmith.
In 1889, Colt introduced the Model 1889, the first truly modern double action revolver, which differed from earlier double action revolvers by having a "swing-out" cylinder, as opposed to a "top-break" or "side-loading" cylinder. Swing out cylinders quickly caught on, because they combined the best features of earlier designs. Top-break actions gave the ability to eject all empty shells simultaneously, and exposed all chambers for easy reloading, but having the frame hinged into two halves weakened the gun and negatively affected accuracy, due to lack of rigidity. "Side-loaders", like the earlier Colt Model 1871 and 1873, gave a rigid frame, but required the user to eject and load one cylinder at a time, as they rotated the cylinder to line each chamber up with the side-mounted loading gate. Smith & Wesson followed 7 years later with the ''Hand Ejector, Model 1896'' in .32 S&W Long caliber, followed by the very similar, yet improved, Model 1899 (later known as the Model 10), which introduced the new .38 Special cartridge. The Model 10 went on to become the best selling handgun of the 20th century, at 6,000,000 units, and the .38 Special is still the most popular chambering for revolvers in the world. These new guns were an improvement over the Colt 1889 design since they incorporated a combined center-pin and ejector rod to lock the cylinder in position. The 1889 did not use a center pin and the cylinder was prone to move out of alignment.
Revolvers have remained popular to the present day in many areas, although in the military and law enforcement, they have largely been supplanted by magazine-fed semi-automatic pistols such as the Beretta M9, especially in circumstances where reload time and higher cartridge capacity are deemed important.