Canada declared war on Germany on September 10, 1939, and sent one division to Europe, which did not have an opportunity to engage in combat before France was defeated by Germany. King's heart was not in the war as he wrote in his diary that if Hitler did not win the war, then Stalin certainly would as he believed that another world war would lead to revolutionary upheaval all around the world, and it would have been much better if the war had been avoided. A sign of King's true feeling about the war came in April 1943, when the mass grave of the Polish officers massacred by the NKVD in Katyn Wood was discovered, which led King to write in his diary that it was the Poles who caused the outbreak of the war in 1939 by refusing to give in to Hitler's demand that the Free City of Danzig be allowed to rejoin Germany, and as such it was the Poles' own fault for the Katyn Wood massacre and everything else they had suffered since 1939. The British historian Victor Rothwell wrote that King's "spiteful" remarks about the Poles causing the war reflected his own resentment at having to declare war on Germany because of public pressure despite his own inclinations towards neutrality.