Roosevelt and Churchill
The friendship between Franklin Roosevelt and Winston Churchill formed the core of the Anglo-American alliance during World War II.
On September 11, 1939 - ten days after Germany invaded Poland - FDR wrote a confidential letter to Churchill, who had just entered the British cabinet as First Lord of the Admiralty. Roosevelt wanted to open a direct line of communication with him. He encouraged Churchill to "keep me in touch personally with anything you want me to know about."
FDR's note was the start of an extraordinary six-year correspondence between the two men that totaled almost 2000 messages.
Between 1941 and 1945, they would also spend 113 days together, beginning with an August 1941 meeting in the North Atlantic and ending at the Yalta Conference in February 1945.