The following post contains SPOILERS for Once Upon a Time in Hollywood. Like, all of them. All of the spoilers. Proceed entirely at your own risk.

At a certain point — maybe it was when Leonardo DiCaprio was burning one of the members of the Manson Family alive with a World War II flame thrower? — you probably realized that Once Upon a Time in Hollywood was not an entirely accurate account of what occurred at 10050 Cielo Drive on the night of August 9, 1969.

Quentin Tarantino never claimed that Once Upon a Time in Hollywood was a biopic, and the finished film makes that pretty darn clear. Still, there are a lot of elements that are based in the real city of Los Angeles circa the late 1960s. In addition to Sharon Tate (played by Margot Robbie) and her husband Roman Polanski (Rafał Zawierucha), and the various members of the Manson Family, there are lots of actual historical figures in the film, and many real pieces of pop culture adorn the various movie marquees and bus advertisements seen in the film.

For a full accounting of the events of August 1969, you should read a book (there are many; this is probably the most famous) or listen to the carefully researched miniseries of the You Must Remember This podcast about Charles Manson and his life in Hollywood. What follows is a quick primer on the facts and the fictions to whet your appetite for a deeper dive into this world.

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