Unlocked: A Brief History of Keys

Lock and key in France, 1950

Well before there was a need to enter individual units of an apartment building or secure clothes inside a gym locker, people sought to keep thieving hands away from their stores of grain or precious jewels. As a result, locks and keys have been around for a large chunk of recorded history.

While both have undergone numerous alterations in accordance with ever-updating technologies, the story of keys is perhaps more personal to the human experience as the portable component that has accompanied us on our journeys over the years. Here’s a look at how these pronged keepsakes have changed since they first surfaced in the ancient world.

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The First Keys

According to Eric Monk’s Keys: Their History and Collection, the oldest known lock is a wooden specimen unearthed from the ruins of the Palace of Sargon in Dur-Sharrukin (modern-day Khorsabad), near the Assyrian capital of Nineveh. As a similar version was found displayed on frescoes at the Karnak temple complex in Egypt, this style of “Egyptian lock” is believed to be in the neighborhood of 4,000 years old.

This early form of security entailed sliding a wooden board through a slot across a door, with movable pins above the slot dropping through corresponding holes in the board to keep it bolted in place. The key for this type of lock was another long piece of wood, sometimes measuring more than 2 feet, with pegs on the end to push the pins back through the holes and allow the board to be released from the bolting position. While these locks were originally fitted to the outside of a door, a hole cut next to the lock enabled a person to reach through and operate the lock from the inside.

Greek and Roman Innovations

The ancient Greeks, meanwhile, developed a different system in which the lock was mounted on the inside of the door. Unlocking from the outside again involved reaching through a hole, with a sickle-shaped key used to turn the bolt. As with the Egyptian models, these keys were large and were often carried by being slung over the shoulder.

A noticeable difference to methodology arrived with the Romans, who began developing metal locks and bronze keys. Romans employed the use of "wards," which were obstacles built within the locks that could only be bypassed by keys of specific shapes. This led to the development of teeth and cut-out shapes within the "bit," the end of a key that engages the bolt.

The Romans also popularized the use of small keys that fastened to a ring and could easily be carried in the palm of the hand. These keys were typically used for boxes that stored valuables within a home and as such were used to signify the wearer's affluence.

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Medieval Touches

Key ornamentation progressed to a remarkable degree through the long period of the Middle Ages, which eventually saw bronze keys phased out in favor of iron. While some medieval keys were small, others surpassed 9 inches in length. This served the same purpose as the Roman ring keys, to project the wealth and prestige of the owners of such magnificent instruments, with the added benefit that these plus-size keys were less likely to be lost than tinier versions.

Early medieval bits featured a cutout cross or another simple cleft to bypass a built-in ward, but were eventually fashioned with teeth and other irregular shapes. The handle, or "bow," also underwent a series of stylistic changes, from the loops and ovals of the eighth century to the kidney shape, often intricately designed, of the 15th century. By this time, many keys were also embedded with a "collar" to stop them from being pressed too far into holes.

By the 17th century, bows were sometimes designed with animal motifs, initials, or a coat of arms. Ceremonial keys also soon came into vogue, including the gilded "chamberlain's keys" that once served a functional purpose in European royal courts but evolved into ornaments for special occasions.

Industrialization and Mass Production

As mentioned in Keys: Their History and Collection, the attention to craftsmanship failed to solve an enduring problem: Most locks were capable of being picked by a person with the dexterity and patience to make the effort. This sparked a focus on stronger security measures in the second half of the 18th century, and the revival of ancient Egyptian methodology with English locksmith Robert Barron's introduction of a twin-tumbler lock in 1778.

Six years later, English inventor Joseph Bramah unveiled an even stronger lock that featured spring-loaded sliders spaced around a pin. A small, cylindrical key embedded with notches corresponding to the height and depth of each slider engaged the pin, enabling the key to turn.

While inventors on both sides of the Atlantic competed to produce the strongest locks over the first half of the 19th century, their creations were too expensive for the general public to afford. That meant old-fashioned (and easily pickable) warded locks remained commonplace around homes, to be locked and unlocked by hefty iron keys.

However, the industry changed for good after the invention of the Yale lock. Patented by Linus Yale in 1844 and perfected by Linus Yale Jr. over the next two decades, this lock required the insertion of a flat, serrated key that raised a series of spring-loaded tumblers to varying heights.

The Yale products became prototypes of the types of keys that remain widely in use today, and with the invention of specialized machinery by the end of the 19th century, the manufacture of locks and keys moved into an era of mass production that made these items more affordable.

Nowadays, keys for homes and valuables are typically made from materials such as nickel silver, brass, and steel. But the development of key cards in the 1970s marked a turn away from metal, and innovations in biometrics have hinted at a future in which fingerprints and facial recognition technology become the norm for entry.

Ultimately, physical keys may wind up being a relic of the past, much the same way as those clunky old door openers from Egypt and Greece are to us today.