General Order No. 3 doesn't use the exalted language of some other documents central to American history.

But for the generations of African Americans who have celebrated Juneteenth, General Order No. 3 is so powerful that it is sometimes read aloud to mark the occasion, alongside or instead of the Emancipation Proclamation.

The order, issued in Galveston on June 19, 1865, by U.S. Maj. Gen. Gordon Granger, informed the people of Texas that all enslaved people were now free:

"The people of Texas are informed that, in accordance with a proclamation from the Executive of the United States, all slaves are free.

Plante found that book Thursday in the stacks of the National Archives Building in Washington, D.C., and located the now-famous order within — handwritten by the major general's aide, F.W. Emery, and still in good condition.

Christopher Wilson, who leads the African American History Program at the National Museum of American History, points to the last time the original Emancipation Proclamation went on tour outside D.C. For conservation reasons, the original can only be displayed for a few days at a time under extremely low light — and he says people lined up at museums across the country to catch a glimpse, even at 2 in the morning.