An English painted wrought iron Optician's sign, circa 1870

The existence of trade signs as a means of identification, in a mainly illiterate society, came into being during the reign of Charles I. In 1625 the legal right was granted to the citzens of London to erect signs outside both homes and businesses. The over-sized symbol, such as the spectacles for the frame maker or Optician, the fish for the fishmonger and key for the locksmith, were among the more obvious early marketing devices.