Summarize the narrative Churchill present

Our idea of the wartime 'Big Three' may be derived from their photographs together at Teheran in 1943 and at Yalta in 1945; it is well to be reminded that these were the only occasions at which they met as a group. On the other hand, Churchill and Roosevelt met together on eleven occasions (including the Atlantic Conference before the US entered the war) and Churchill and Stalin on three occasions. Roosevelt and Stalin never met except on the margins of the two trilateral meetings. In so far as a triumvirate existed, it was a matter of communications through messages or intermediaries. Room for misunderstanding was always present. How could this not be the case since their countries, their personal philosophies and national objectives were so different? What united them was the determination between June 1941, when Hitler invaded the Soviet Union, and the end of the European war (by which time Roosevelt was dead) that Hitler's Reich should suffer total defeat and Nazism be extirpated. Everything else was problematic and contingent.