Archeologists found the oldest known lock in the Khorsabad palace ruins near Nineveh. The lock was estimated to be 4,000 years old. It was a forerunner to a pin tumbler type of lock, and a common Egyptian lock for the time. This lock worked using a large wooden bolt to secure a door, which had a slot with several holes in its upper surface. The holes were filled with wooden pegs that prevented the bolt from being opened.

The warded lock was also present from early times and remains the most recognizable lock and key design in the Western world. The first all-metal locks appeared between the years 870 and 900, and are attributed to the English.

Affluent Romans often kept their valuables in secure boxes within their households and wore the keys as rings on their fingers.

During the period of the 18th and 19th centuries, in part to the onset of the Industrial Revolution, many technical developments were made in the locking mechanisms that added to the security of common locking devices. It was during this period that America changed from importing door hardware to manufacturing and even exporting some.

The earliest patent for a double-acting pin tumbler lock was granted to American physician Abraham O. Stansbury in England in 1805, but the modern version, still in use today, was invented by American Linus Yale, Sr. in 1848. But, other famous locksmiths patented their lock designed before and after Linus.

Robert Barron

The first serious attempt to improve the security of the lock was made in 1778 in England. Robert Barron patented a double-acting tumbler lock.

Joseph Bramah patented the safety lock in 1784. Bramah's lock was considered unpickable. The inventor went on to create a Hydrostatic Machine, a beer-pump, the four-cock, a quill-sharpener, a working planer, and more.

James Sargent

In 1857, James Sargent invented the world's first successful key-changeable combination lock. His lock became popular with safe manufacturers and the United States Treasury Department. In 1873, Sargent patented a time lock mechanism that became the prototype of those being used in contemporary bank vaults.

Samuel Segal

Mr. Samuel Segal (former New York City policeman) invented the first jimmy proof locks in 1916. Segal holds over twenty-five patents.

Harry Soref

Soref founded the Master Lock Company in 1921 and patented an improved padlock. In April 1924, he received a patent (U.S #1,490,987) for his new lock casing. Soref made a padlock that was both strong and cheap using a case constructed out of layers of metal, like the doors of a bank vault. He designed his padlock using laminated steel.

Linus Yale Sr.

Linus Yale invented a pin-tumbler lock in 1848. His son improved upon his lock using a smaller, flat key with serrated edges that is the basis of ​the modern pin-tumbler locks.

Linus Yale Jr. (1821 to 1868)

American, Linus Yale Jr. was a mechanical engineer and lock manufacturer who patented a cylinder pin-tumbler lock in 1861. Yale invented the modern combination lock in 1862.