During the Teheran Conference, President Franklin D. Roosevelt and Prime Minister Winston Churchill agree to inform Marshall Joseph Stalin of a firm date for launching Overlord.
When the recommendations of the Combined Chiefs of Staff were presented to Roosevelt they read- "Agreed-to inform Stalin that we will launch Overlord by June 1... " Roosevelt penciled in "During the month of May" to placate Churchill because this was the time-frame agreed upon earlier in 1943 by both men.