Executive Order 3336—Ordering Flags at Half-Mast in Memory of American Dead in World War
October 08, 1920
The White House, October 8, 1920.
I hereby direct that on Sunday, November 14, 1920, the flag of the United States be displayed at half-mast at all military posts, naval stations, on vessels, and on buildings of the United States, as a token of the Nation's participation in the memorial services held for the heroic American soldiers, sailors, marines and others who gave their lives to their country in the World War.
WOODROW WILSON
Woodrow Wilson, Executive Order 3336—Ordering Flags at Half-Mast in Memory of American Dead in World War Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/350388