Half the challenge of presidential security in centuries past was just knowing where the president was. No official flag existed to signify the commander-in-chief’s presence aboard — the Navy manual kept going back and forth each year between having ships fly the American ensign flag and the American Union Jack. The Army had designed their own own flag, with the U.S. coat of arms on a scarlet background. The matter was complicated more when President William Taft issued an order to make the background blue, which inverted the coloring on the Army flag. Finally, it fell to President Woodrow Wilson, in consultation with Secretary of the Navy Franklin D. Roosevelt and others, to develop a single presidential flag.

On this day, May 29, in 1916, President Wilson signed Executive Order standardizing American flag colors and sizes (the latter of which Wilson found in 66 different varieties.)

Only minor changes remained after that. President Truman changed the eagle to face towards its right, towards the olive branch, symbolizing the preference for peace. Truman also unified the coat of arms, flag, and seal to use the new design, very much like the presidential seal we see today. Two days later, the flag first flew at the commissioning of the aircraft carrier.