Beginning in the 1750s, some American insurance companies issued metal fire marks to policyholders to signify that their property was insured against fire damage. The fire marks bore the name and/or symbol of the insurer, and some included the customer’s policy number. The company or agent would then affix the mark to the policyholder’s home or business. For owners the mark served as proof of insurance and a deterrent against arson. For insurance companies the mark served as a form of advertising, and alerted volunteer firefighters that the property was insured.
The Firemen's Insurance Company of Baltimore, Maryland issued this fire mark in 1855. The circular cast iron mark has a raised image of a Philadelphia-style double-deck end stroke engine in the center, with a raised text below that reads “F.I. CO.” The text and parts of the engine have been painted gold, which has chipped at points. The Firemen's Insurance Company was founded in 1825, but folded in 1904 due to the losses suffered in the Great Fire of Baltimore.