Complex sentence: In the Army, the rank bore no insignia other than a brown sleeve braid on blouses and an officer's cap device and hat cord until December 1917, when a gold bar similar to the silver bar of a first lieutenant was introduced.
Split into simpler sentences: In the Army, until December 1917 the rank bore no insignia other than a brown sleeve braid on blouses and an officer's cap device and hat cord. In December 1917, a gold bar similar to the silver bar of a first lieutenant was introduced.