Fire marks and fire insurance date back to the Great Fire of London, in 1666. As British insurance companies sprang up in response to the fire, each formed their own fire brigades. The brigades used fire marks, or plaques to determine whether they were responsible for protecting the house or business in question from fire.
This idea was brought to the U.S. when Benjamin Franklin started the Philadelphia Contributionship for the insurance of houses from loss of fire in 1752. America already had volunteer fire brigades, so the marks were not needed to move the firefighters in to action, but they did serve as proof for the property owner and advertising for the insurance company.
Some of the marks were made of lead, copper, tinned iron, zinc, brass and ceramic. They bore the logo of the insurance company. Some logos were firemen, coat of arms, trees (because of Ben Franklin's theory that trees attracted lightening, causing fires to spread and hampered fire fighting equipment; insurance companies refused to issue policies for building surrounded by trees), the sun, hand-in-hand symbol, and many others. Click here to view historic fire marks.
Some accounts claim that fire brigades would not put out a fire that was not marked. Some suggest these marks were just advertisement for insurance companies. The custom lasted for more than a century, until the organization of city fire departments. This alleviated the idea of separating adequately insured property owners from those who could not afford to pay for protection.
Some marks are still on original buildings; however, these prized marks are often in the hands of collectors or in museums keeping the history of firefighting alive.