Chewing gum has no definitive date of invention, as historically many cultures worldwide chewed on the resin of trees. The oldest evidence as of 2014 is a 5,000-year-old piece of gum made from birch bark tar, found by archaeologists in western Finland in 2007.
Other cultures used different tree resins as gums. The ancient Greeks chewed gum from the resin of the mastic tree, while the Aztecs used a gum preparation called chicle from the latex of the rubber tree as an oral antiseptic and adhesive. Native American cultures took sap from spruce trees to make a chewing gum. The first U.S. patent for modern chewing gum was granted to William Finley Semple in 1869.