Greenbacks were emergency paper currency issued by the United States during the American Civil War that were printed in green on the back.
They were in two forms: Demand Notes, issued in 1861–1862, and United States Notes, issued in 1862–1865.
Paper money in the United States dates back to 1690 and represented bills of credit or IOUs.
New currencies were introduced in the U.S. in 1861 to help finance the Civil War.
In 1996, a series of bills were introduced that used new methods to prevent counterfeiting.
The first paper money issued by the government were "demand notes" commonly referred to as "greenbacks." In 1862, Congress retired the demand notes and began issuing United States notes, also called legal tender notes.