On July 30, 1956, two years after pushing to have the phrase
“under God” inserted into the pledge of allegiance, President
Dwight D. Eisenhower signed a law officially declaring “In
God We Trust” to be the nation’s official motto.

The law, P.L. 84-140, also mandated that the phrase be printed
on all American paper currency. The phrase had been placed
on U.S. coins since the Civil War when, according to the
historical association of the United States Treasury, religious
sentiment reached a peak. Eisenhower’s treasury secretary, 
George Humphrey, had suggested adding the phrase to
paper currency as well.

Two years before making ‘In God We Trust’ the national
motto, President Eisenhower (center) introduced a stamp
carrying the slogan (below).