The principle on which it was based gave rise to many ingenious inventions over the millennia. It is thought that the first locks were made in Mesopotamia, according to evidence discovered in the palaces of Nineveh in Iraq. Writing was also invented in those lands, and it was in writing that locks found new expression: 'Nin-dada, the daughter of Lu-Ninurta, did not open her mouth, her lips remained locked.' This sentence is from the world's first recorded court judgment inscribed on a Sumerian clay tablet around 1850 BC. Nin-dada refused to tell the authorities the identity of the three people who killed her husband.
In the ancient statutes of Mesopotamia a law uses the same metaphor: 'If a son should declare to his father, "You are not my father," he [the father] shall sever the locks of him [the son], make him a slave and sell him for money.'
So begins the known story of locks and keys. Now let us go in search of these two fascinating inventions, which were not just symbols of security, but at the same time of power, authority and prestige.