From the first century AD Romans secured their valuables in locked coffers. Rings with a key attached ro the bezel like this one could be used to open them. Examples have been found in bronze, but also in more precious metals, many of which in Pompei. The type continued in use during the early medieval period. This very practical function doubled up with a more status related function. Persons wearing these keys were the only one having the right to accees the family money and jewellery.