What is the fine-grained topic of the following text: He joined the 58th Battalion in France on 23 February 1916 and was promoted to Lance Corporal on 4 March 1916, to Corporal on 6 August 1916 and to Sergeant (Sgt) on 22 March 1917. Only return the topic.
Military promotions of a soldier in the 58th Battalion during World War I