A law passed by the 84th Congress (P.L. 84-140) and approved by the President on July 30, 1956, the President approved a Joint Resolution of the 84th Congress, declaring IN GOD WE TRUST the national motto of the United States. IN GOD WE TRUST was first used on paper money in 1957, when it appeared on the one-dollar silver certificate. The first paper currency bearing the motto entered circulation on October 1, 1957. The Bureau of Engraving and Printing (BEP) was converting to the dry intaglio printing process. During this conversion, it gradually included IN GOD WE TRUST in the back design of all classes and denominations of currency.


I was wrong, it was just over 50 years, kept thinking 1940's for some reason but it was later. It was put on there for the Communism scare to make people feel better about it for some reason. Though from that, it didn't start appearing on the paper bills until 66-68. Again, we're far from a "Christian nation" and the only reason it was allowed to stay on money...was that it didn't specify a specific God, just A GOD.