The EPIX Original Documentary, "Forgotten Four: The Integration of Pro Football," which premiered on Tuesday at 8 p.m. on EPIX, is a provocative and essential story about civil rights trailblazers that needed to be told.

Kenny Washington, Woody Strode, Marion Motley and Bill Willis are not household names, nor do they make an appearance in history books, but these four African-American men played an indispensable role in breaking down color barriers and clearing the path so that non-Anglo players could compete in the world of football, as well as other sports.

"Forgotten Four" begins with the children of these men recalling fond thoughts of their fathers. Viewers are then immediately introduced to the racial violence and racial divide of the 1940s. America's ongoing injustices persisted as violence was the law of the land. The only solace for many blacks was being an athlete and playing football in college. Success in football showed that "the door" was open, even if just a crack, allowing temporary colorblindness.

But, professional sports communicated the prevailing attitudes of the nation, and the owner of the Washington Redskins, George Preston Marshall, was racist and had an astounding opposition to integrating. He barred Kenny Washington from signing with the Chicago Bears following success in college, and "color lines" were made to keep black players who were electrifying on the field in their place. They were reminded, "when you're on the field, you're a star. And when you leave the field, you're a ni**er."

"Considered by West Coast fans the most brilliant player in the U. S. last year, Washington cannot play major-league pro football because he is a Negro," said Time magazine in 1940

The color of Washington's skin proved to be more important than the pigskin that he and other black players toted around the field. When playing for UCLA, he and his three black teammates, Woody Strode, Ray Bartlett and Jackie Robinson transformed the game on a nightly basis, and although Washington was the absolute best, it didn't seem to matter.

But, in 1946, Washington was able to finagle his way onto the Cleveland Rams when they moved to L.A., and he became the first black player to sign a contract with National Football League team post-World War II. When signing, he demanded that Strode be able to join him, although that request met a great deal of resistance because Strode had married outside of his race. Nonetheless both men became professional athletes, and although their football careers were short-lived, the two men made a huge impact on the sport.

In another part of the country, Paul Brown, owner of the emerging The Cleveland Browns, was creating a place for black athletes. According to sources, it never occurred to Brown that everyone shouldn't have an equal chance, so he brought in Bill Willis, and three days later Motley, a 240-pound athlete who was a "son-of-a-bitch on the field" and could do it all, auditioned for the Browns and was accepted.

While the documentary shows the progression and growing acceptance of black players in the NFL, it did not shy away from persisting struggles. Some players were "put in the butcher shop" and pummeled by their own teams as well as the opposition. Because of threats, black players couldn't gather socially off of the field, and black players were often put into the game just to protect them from their own teammates. On one occasion, Brown paid Motley and Willis $500 to stay behind when the team went to Florida, knowing that it would endanger them to go there. Threats on and off the field played a significant role in their careers being short.

The film, produced by Ross Greenburg, is an outstanding account of broken color barriers in pro football. Historically, they were overshadowed by the success of Jackie Robinson, who had played alongside Strode and Washington on the UCLA Bruins football team in 1939, and Branch Rickey in Major League Baseball the year after the Forgotten Four had shown that they were pioneers and able to forge change. Their struggle in the world of football made it possible others to excel in their chosen sport.

Follow EPIX on Twitter , on Facebook, YouTube and Instagram.