Like other handy tools, the pocket knife was not invented so much as it was a product of evolution. Over centuries, the fixed-blade knife used by hunters and soldiers became the folding knife -- still used by hunters and soldiers -- but also used by coachmen, tradesmen and others as a utilitarian tool. During its evolution over centuries, individually made single-bladed knives began to be mass-produced by modern manufacturers like Victorinox. Near the turn of 19th century, knives picked up additional blades, saws, leather punches, scissors and even toothpicks to aid functionality until they became virtual pocket toolboxes.

Simple Fold Saves Cuts

Not surprisingly, solders and travelers were some of the first people to use pocket knives regularly. By carrying a lot of gear over treacherous terrain and getting into all sorts of cramped and peculiar postures, a soldier was destined to cut himself on his own knife at some point. Travelers also needed a smaller, less bulky tool than a sword for eating and utilitarian purposes. Somewhere along the way, one clever person invented a way to collapse the knife blade into its handle, and the first folding knife was born. The earliest folded knives -- such as one found in Halstatt, Austria, believed to have been fashioned as early as 500 to 600 B.C. -- were bronze. A middle-Roman era (201 to 300) specimen, found in the Mediterranean area, is particularly interesting. Made of silver with an iron blade and containing a full set of dining cutlery, it appears to be an early forerunner of the multipurpose Swiss Army knife.

The Single Blade

Not all folding knives were quite so elaborate as that Roman multitool. Most early pocket knives were unpretentious blades that pivoted into a sheath without the help of springs. Folding knives predating Roman times have been found in burials in the Iberian Peninsula. Later, Roman soldiers carried similar knives into battle. These early knives were weapons and only necessitated a sharp blade. The average blade length would have been around 3 inches, so the folding knife would have made up only a minor part of the weaponry a Roman soldier brought to war.

From Weapon to Delicate Tool

Centuries later, the plain, spring-less folding knife was still in use, though more as a tool for coachmen and travelers than a soldier's weapon. It was not until the 1600s, in the city of Sheffield, England, that uniform, slip-joint knives began to be made with springs along the back for holding the blades open or closed. With the addition of new manufacturing methods allowing the manufacture of reasonable quantities of these safer and better-working pocket knives, people of all walks began carrying them. The pen knife -- a small pocket knife designed for trimming the writing tips of quill pens -- became an essential part of the pocket contents of both gentlemen and ladies.

More Than a Blade

Around the 17th century, knives began to drift away from simple one- or two-bladed designs to more specific and useful tools. These later pocket knives would have been carried by people of all vocations from farmers to leather workers and hostlers. Makers of pocket knives for specific everday uses include Joseph Rodgers -- granted a trademark in 1682 -- and George Wostenholm -- trademark registered in 1787. Today, both still make pruners, skinning knives, gentleman's pocket knives, stockman's knives and pen knives, among other specialty knives.

Modern Knives for Soldiers and Sailors

In the 19th century, Victorinox, makers of the famous Swiss Army knife, brought multitool pocket knives into the limelight with regular issue knives for solders. The officer's version included a corkscrew for wine. Early on, sailors carried ordinary pocket knives with deliberately rounded blades to prevent accidents and serious injuries aboard ship, but they later used manufactured knives, many made by small independent cutlery makers such as Ibberson. These came with rounded blades and other tools specifically designed for rope working. Ibberson is also notable for the first knife made with stainless steel, created in 1913.