It’s hard to imagine now that there was ever a time when American football didn’t have a strong pressence of black athletes, but it wasn’t until 1946 that four African-American players broke professional football’s color line. Now a film that’s set to debut next month is out to tell their stories.

The men in question are Kenny Washington, Woody Strode, Marion Motley and Bill Willis , four little-known players who integrated the game one year before Jackie Robinson did the same for Major League Baseball with the Brooklyn Dodgers. The film is scheduled to premiere on EPIX on Tuesday, September 23 at 8 p.m. ET, but you can watch the trailer above.

(h/t Shadow and Act)