A historic 21 gun salute on President's Day.

The practice of firing cannons or rifles as a salute of honor is nearly as old as gunpowder weapons themselves. The U.S. Army Center of Military History traces cannon salutes back to the 14th century, noting that the number 21 arose when a battery of seven guns fired three times. Today, such salutes signify high honor to the person or occasion being saluted.

A Sign of Honor

The U.S. Navy formalized the 21-gun salute to honor the president in 1818, according to the Naval Historical Center. In 1842, the Navy standardized the practice and included “National Salutes” on Washington’s birthday and Independence Day. Today, a 21-gun salute honors visits not only by presidents, but also vice presidents, presidents-elect and former presidents. It also marks the funeral of a president or former president, being fired at noon on the day of the funeral. In addition, the U.S. military fires a 21-gun salute to honor a foreign flag and to salute a visiting foreign head of state or member of a reigning royal family. Such salutes show the nation’s formal respect.