Washington - Juneteenth - the holiday now being embraced by Nike, Google, the NFL and the state of New York in the wake of police brutality protests - is one of the oldest celebrations commemorating the end of slavery in the United States.
It has its roots in the long-awaited moment of emancipation in Texas, where more than 250,000 enslaved black people received news on June 19, 1865 - more than two years after President Abraham Lincoln's Emancipation Proclamation - that they were free.
Texas slave owners had refused to acknowledge the end of the Civil War and the Emancipation Proclamation.
"Black people were in such a delicate situation in Texas," said C.R. Gibbs, a historian and author of "Black, Copper & Bright: The District of Columbia's Black Civil War Regiment." "You have the collapse of the Confederate government. And roving bands of men who wanted to turn the clock back. A Union officer once said, 'Given a choice between hell and Texas, I would live in hell and rent out Texas.' It was just that bad in Texas."
Then, on June 19, 1865, Major General Gordon Granger landed on Galveston Island with more than 2,000 Union troops. He stood at the Headquarters District of Texas in Galveston and read "General Order No. 3":
"The people of Texas are informed that, in accordance with a proclamation from the Executive of the United States, all slaves are free."
Black people who heard the news erupted in what Gibbs calls "a moment of indescribable joy."
Celebrations of Juneteenth - which combines the word June with Nineteenth - began in 1866, a year and a day after Granger's announcement.
Black men, women and children dressed in their finest attire and gathered to sing spirituals, pray, play baseball and eat. Often the menus included fried chicken, cornbread, greens and handmade strawberry soda.
"The red color of the soda symbolized blood shed during slavery," Gibbs said.
There would be special invitations for the oldest freed men and women to recount the horrors of slavery and the sweetness of freedom.
"This was partying with purpose - not only for the people to join the celebration but to learn directly from the past," Gibbs said.
Another powerful ingredient in early Juneteenth celebrations was that the early festivities took place on land owned by black people.
"There was an extra sense of pride," Gibbs said. "It was a matter of racial pride and uplift to show even in the face of searing racial hatred, 'We are property owners.' It showed progress.
The struggle for freedom had not ended with the Emancipation Proclamation. "The Emancipation Proclamation was limited in many ways" according to the National Archives website. "It applied only to states that had seceded from the Union, leaving slavery untouched in the loyal border states. It also expressly exempted parts of the Confederacy that had already come under Northern control. Most important, the freedom it promised depended upon Union military victory."
So even after the Confederate surrender at Appomattox, "there was still slavery in Kentucky, New Jersey and Delaware," Gibbs said. "That is one of the reasons we needed the 13th Amendment. We needed the 13th Amendment to shut down slavery."
The 13th Amendment to the U.S. Constitution formally abolished slavery in the United States, declaring that: "Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction." Congress passed the 13th Amendment on Jan. 31, 1865. It was ratified on Dec. 6, 1865.
Slavery was so deeply embedded in the country's history that the resistance to ending it was fierce, especially among slaveholders.
Perry Downs, a brother of famed abolitionist Frederick Douglass, was enslaved in Texas. "He was in Texas when Emancipation was proclaimed and heard his master say he had "run his property into Texas and if he needed to he would take his property to Cuba." The story is told in a book called "Frederick Douglass: The Colored Orator."
Even after freedom came in Texas, black people who stayed there lived under oppressive racial terror, Gibbs said.
Between 1865 and 1930, more than 450 lynchings were recorded in Texas, according to the book "In the Cult of Glory," by D.J. Swanson. The book reveals that Texas Rangers often stood aside as the lynchings were carried out.
"It is an incredible indicator of how lawless Texas was and how racist Texas was," Gibbs said. "There were lynchings and torture. They would torture somebody they've already lynched. In 1893, they claimed a black man killed a white girl, they tortured him with red hot irons and put his eyes out. Texas Rangers refused to intervene."
That brutal history is part of what makes Juneteenth a unique holiday. "The celebration of Juneteenth can be seen as active resistance," Gibbs said.
Juneteenth celebrations spread across the country as black people fled Texas. "Anywhere black Texans emigrated, anywhere they went, they took the celebration with them," Gibbs said.
Because freedom came to enslaved black people at different times, Emancipation celebrations are often called by different names and take place on different dates.
In the nation's capital, for example, the city celebrates Emancipation Day on April 16 to commemorate the date in 1862 when more than 3,000 enslaved black people in D.C. were freed nearly eight months before Lincoln issued the Emancipation Proclamation.
But the best known freedom celebration, Gibbs said, is Juneteenth.
"Many people are not aware of freedom celebrations in their own state or municipality," he said, "but everybody has heard of Juneteenth."