The U.S. Congress added the words "under God" to the Pledge of Allegiance in 1954 in response to the Communist threat of the era. The bill adding this phrase was signed into law on June 14, 1954 by President Dwight Eisenhower, a vocal supporter of the change.
The Pledge of Allegiance was written in 1892 by Francis Bellamy, a Baptist minister who was serving a church in Boston at the time. Bellamy wrote the pledge for schoolchildren who were participating in a patriotic event held at the opening of the Columbian Exposition in October 1892. Following this event, the Pledge of Allegiance was recited at schools throughout the nation and was made an official part of the national flag code when it was adopted by the U.S. Congress in 1942.