Complex sentence: In February 1918, he was promoted to temporary brigadier-general to command the 159th (Cheshire) Brigade, in the 53rd (Welsh) Division, which under his command captured the Mount of Olives at Jerusalem.
Split into simpler sentences: In February 1918, he was promoted to temporary brigadier-general to command the 159th (Cheshire) Brigade, in the 53rd (Welsh) Division. Which under his command captured the Mount of Olives at Jerusalem.