I hate that I missed this.

On December 15, 1791, the ratification of the first ten amendments to the Constitution of the United States of America by three-quarters of the states took place. These were subsequently incorporated into the Constitution and became known as the Bill of Rights. December 15th has been known as Bill of Rights Day since 1941 when President Franklin D. Roosevelt proclaimed it as such, noting the 150th anniversary of this ratification. President Roosevelt urged all Americans to display the flag on this date, and to plan appropriate ceremonies honoring the occasion.