Fighting a war is one thing, paying for it is another. Both sides resorted to borrowing, taxation, issuing treasury bonds, and printing money to finance the war. The Confederacy relied more heavily on printed money, which devalued quickly without a gold standard behind it. Backed by a more stable economy, Northern currency better retained its value. The distinctive green ink on the reverse of Northern bills led them to be called “greenbacks,” still a synonym for paper money.