You’ve heard of the movie Green Book by now, but do you know the history behind the real green book?

The movie Green Book starring Viggo Mortensen (Lord of the Rings, A History of Violence) and Mahershala Ali (Moonlight, True Detective) just won the 2018 Golden Globe for Best Motion Picture – Musical or Comedy. The film is based in the 1960s and is based on the true story of black musician Don Shirley and his driver, a white man named Tony Vallelonga. As the two travel through the south, they mend their differences and bond in a time of great racial inequality. If you haven’t seen the movie yet, do you know the history behind the film’s title?

In the time of Jim Crow laws, a postal worker from New York put together The Negro Motorist Green Book, which listed establishments that allowed mixed race patronage. In that era, it was not uncommon for blacks to be turned away from white-only restaurants and hotels; the book was essential for all African-American road-trippers.

While the book was a saving grace for many back in the time of Jim Crow laws, it is a very sad commentary that it needed to be published at all. But in a time when many non-whites feared for their lives, the green book was a necessary evil. Find out even more about the history of the book in the video below: