when did the military start using dog tags
Dog tag The earliest mention of an identification tag for soldiers comes in Polyaenus (Stratagems 1.17) where the Spartans wrote their names on sticks tied to their left wrists. A type of dog tag ("signaculum"), was given to the Roman legionnaire at the moment of enrollment.[2] The legionnaire "signaculum" was a lead disk with a leather string, worn around the neck,[3] with the name of the recruit and the indication of the legion of which the recruit was part. This procedure, together with enrolment in the list of recruits, was made at the beginning of a four-month probatory period ("probatio"). The recruit got the military status only after the oath of allegiance ("sacramentum"), at the end of "probatio", meaning that from a legal point of view the "signaculum" was given to a subject who was no longer a civilian, but not yet in the military.
Infantry Blue Cord A light-blue cord was created to be worn over the right shoulder of both officers and enlisted men. Also, light-blue plastic disks were issued to be placed behind the metal "crossed rifles" Infantry branch of service insignia disks as well as on the disc service cap insignia. The new enhancements were first worn by the 3rd US Infantry Regiment ("The Old Guard"). The light-blue cord and disks became standard for all Infantrymen in 1952.