Another bit of historical trivia about Gun Salutes.
Gun or cannon salutes, used to honor distinguished persons or to mark special occasions, originate from the practice of firing all guns of a battery, fort or ship as a token of disarming them, because early guns were not speedily reloaded.
Modern gun salutes are fired with blank cartridges or charges. The number of shots is prescribed by international custom and agreement.
Referred to as the royal salute, the 21-gun salute is fired for chiefs of state, heads of government, members of a reigning royal family and others of comparable rank. Salutes of 17, 15, 13, 11, seven, and five shots are fired for people of lesser rank.
Firing an odd number of shots is believed to stem from an ancient naval superstition that an even number of shots is unlucky.