Uniform of the Union Army letters US. Officers, NCOs and cavalry troopers were equipped with a sword belt with a rectangular buckle with eagle motif. Rank was displayed on epaulettes (dress occasions) or shoulder straps(field duties): no insignia for a second lieutenant, one gold bar for a first lieutenant, two gold bars for a captain, a gold oak leaf for a major, a silver oak leaf for a lieutenant colonel, a silver eagle for a colonel and one, two or three silver stars for a general, depending on his seniority. The color of the shoulder strap fields – with trims in gold braid – were
United States Army officer rank insignia the gold leaf which the major had been wearing on the shoulder strap. In the same year, the bars on the shoulder straps of the captains and first lieutenants were changed from gold to silver. By 1917 and the time of World War I, the olive drab service uniform had gradually become used more frequently and the blue uniform was worn only on formal dress occasions. As a result, metal insignia was authorized for wear on the service uniform on the shoulder loop and on the collar of the shirt when worn without a jacket. Shortly after the United States