Complex sentence: Experience of writing the history of the South African War, showed that delay made the task impossible if the collection of material for the work did not begin at once and in May 1915, Captain C. T. Atkinson was sent to France to collect unit diaries.
Split into simpler sentences: Experience of writing the history of the South African War, showed that delay made the task impossible and that the collection of material for the work should begin at once. In May 1915, Captain C. T. Atkinson was sent to France to collect unit diaries.