Complex sentence: He was promoted to General der Infanterie on 18 August 1916 and 10 days later he assumed command of the newly formed General Command No.52, a.k.a. the Danube Army; that was used in the Bulgarian Danube region.
Split into simpler sentences: He was promoted to General der Infanterie on 18 August 1916. Ten days later he assumed command of the newly formed General Command No.52, a.k.a. the Danube Army; that was used in the Bulgarian Danube region.