In 1939 the Second World War started. This is a fact. This a historical true. Correct?
It is generally assumed so but in fact it's not true. Stalin had said in his summary report of the XVIII congress of the Communist Party in March of 1939:
"Уже второй год идет новая империалистическая война, разыгравшаяся на громадной территории от Шанхая до Гибралтара и захватившая более 500 миллионов населения. Насильственно перекраивается карта Европы, Африки, Азии."
Отчетны& #x439; доклад на XVIII съезде партии о работ
So, according to his point of view from that historical period of time, the WWII began in 1937.