Saluting is a military custom by which a soldier signals acknowledgement of the due respect to a superior rank.
Salutes are reciprocated at the highest levels up to and including Heads of State and are indicative of a feeling of mutual trust and respect.
The exact origin of the military salute has been lost in time but it is believed that it originated by showing that the right hand (the fighting hand) was not concealing a weapon.
Another explanation is that when men-at-arms took to wearing armour, the approaching generals or king would ride forward and, holding the reins of the horse with the left hand, they would raise the visor with the right to identify each other.
By the beginning of the nineteenth century, the salute with the hand palm to the front was firmly established.