The Roman salute is a closed finger, flat-palm-down hand raised at an angle (usually 45 degrees) and was used by the Roman Republic.

It was also the historical civilian salute of the United States, from 1787?-1934?, known since 1892 as the Bellamy salute. It was also the historical salute among armies of the Middle East and South America.

Children Saluting the American Flag (year unknown)

When the Nazi party of Germany adopted the Roman salute from the Italian fascists, President Roosevelt instituted the hand over the heart as the salute to be rendered by civilians during the Pledge of Allegiance and the national anthem in the United States. This was done when Congress officially adopted the Flag Code on June 22, 1942.

The association with the Nazis has been so strong that it is rarely used by non-Nazi organizations since the end of World War II. One exception to this is the Republic of China (on Taiwan), where the salute is still used when an office holder is swearing an oath.

The Oath of the Horatii, by Jacques-Louis David