Confederate

In April of 1861, the first issues of the Confederate States of American Dollar were introduced into circulation, just before the American Civil War. 

At that time, it was not backed by hard assets, but instead was a promise to pay the bearer after the war, provided the South won independency. However, as the war tilted against the Confederates, confidence in the currency diminished. By 1863, the confederate dollar, aka "greyback", was only quoted at 6 cents in gold and continued to drop. 

Today, greybacks are considered a prized collector's item.