Because of Ben Franklin's theory that trees attracted lightening, causing fires to spread and hampered fire fighting equipment, insurance companies used to refuse to issue policies for buildings surrounded by trees. The tree fire mark, issued in 1784 by the 40 members of the Philadelphia Contributorship which split off and formed the Mutual Assurance of Philadelphia symbolized their opposition to the accepted belief of the day.
Items depicted: Front of Tree Fire Mark and Back of Tree Fire Mark