Who invented chewing gum, and when was it first used?

Neolithic People, 9000 years ago, chewed some kind of "caveman chewing gum"[1].

Ancient Greece island, Chios, was famous for their Mastiche chewing gums, made from mastic (mastix) tree. Mastic three is very small and grows up to 4m tall. Romans used mastic chewing gums too. Ancient Mayans used the coagulated sap of the Sapodilla tree as chewing gums.

Modern chewing gum was invented in USA in 19th century.

John B. Curtis and his brother (to so some sources father) started selling chewing gums in 1848. They made their first chewing gums of spruce gum.

In 1869. Amos Tyler patented the chewing gum, however he never sold chewing gums himself.

The true inventor of modern commercially successful chewing gum was Thomas Adams. Since 1870. his company Adams & Sons began selling Sour Orange chewing gum, as after dinner "candy". In 1871 Thomas Adams patented a chewing gum making machine.