Born in Ballarat, Victoria and a Farmer by trade, Robert James Caldwell was 21 years and single when enlisted on the 1st of April 1916 in the 5th Battalion, 19th Reinforcement, Australian Imperial Force, with the rank of Private, Number 5984. His Unit embarked from Melbourne, Victoria, on board HMAT A32 'Themistocles' on the 28th of July 1916. Admitted to Hospital sick on the 28th of December 1916; re-joined Unit on the 7th of February 1917; admitted to Bath War Hospital on the 29th of June 1917 suffering with Pyrexia of unknown origin, trench fever; transferred to 1st Auxiliary Hospital on the 26th of July 1917. Private appointed Lance Corporal, France on the 23rd of May 1918 and awarded Military Medal, France on the 22nd of November 1918. Embarked for return to Australia per 'Cluny Castle' on the 23rd of March 1919 and disembarked on the 22nd of May 1919. Discharged on the 29th of June 1919 with Termination of Period of Enlistment. Tree No. 2807