The earliest known lock and key device was discovered in the ruins of Nineveh, the capital of ancient Assyria. Locks such as this were later developed into the Egyptian wooden pin lock, which consisted of a bolt, door fixture, and key. When the key was inserted, pins within the fixture were lifted out of drilled holes within the bolt, allowing it to move. When the key was removed, the pins fell part-way into the bolt, preventing movement.
The warded lock was also present from antiquity and remains the most recognizable lock and key design in the Western world. The first all-metal lock appeared between the years 870 and 900, and are attributed to the English craftsmen. It is also said that the key was invented by Theodore of Samos in the 6th century BC.
Affluent Romans often kept their valuables in secure boxes within their households, and wore the keys as rings on their fingers. The practice had two benefits: It kept the key handy at all times, while signaling that the wearer was wealthy and important enough to have money and jewelry worth securing.