The Leonardo DiCaprio adventure takes the basic facts of real-life frontiersman Hugh Glass's ordeal and adds extra characters, extra ultraviolence and more horse guts.
Hugh Glass was a frontiersman working in the upper Missouri river area in the early years of the 19th century. On a fur trapping expedition in 1823, he was attacked and mauled by a grizzly bear.
Hugh Glass (Leonardo DiCaprio) is one of a group of men finishing up a fur trapping expedition in the wilderness. They are attacked by Ree (Arikara)warriors. Whoosh! Someone gets impaled on a spear. Bang! Someone gets shot off his horse. Crack! Someone's bones shatter. There's an unflinching close-up of an arrow thwacking into a face, a gun butt bashing into a face, a flying kick to a face. A horse gets shot in the face. It's exceptionally well choreographed and filmed.
This scene is based on a real-life incident: In June 1823, Ashley's band of around 70 men was attacked by Arikara warriors –they estimated around 600, though in the film it's more like a dozen.
In the film, 10 men get away. Fitzgerald is fighty and racist, so he's the baddie. Glass is the goodie, because he loves his son (who is half-Pawnee) in a gruff, manly way that involves telling him off a lot. The backstory about Glass’s love for a Pawnee woman is fiction. It has been suggested the real Glass had such a relationship, but there's no firm evidence –and no evidence that he had any children.
As the men make their way through a forest, Glass happens upon two bear cubs and their angry mama. If you felt wan after the face-smashing scene at the start, reach for the smelling salts. Chomp! Growl! Shake! The bear sniffs him to see if he's dead, then jumps up and down on his back. Splinter! Howl! Slash! Glass shoots the bear. Anyway, while historians are not certain of the precise details, the real Glass did get into a fight with a real bear, some time in August 1823.
The men find Glass in a rum old state. Captain Henry pays Fitzgerald, Bridger and Hawk to stay behind until it is time for Glass's inevitable burial. When the captain leaves, Fitzgerald tries to bump Glass off. Hawk interrupts, so Fitzgerald bumps him off instead. This didn't happen in real life, because Hawk didn't exist. In the film, the ailing Glass sees Fitzgerald kill his son, giving him an extra motivation to stay alive and seek revenge.
The real Glass survived his abandonment and dragged his battered body over hundreds of miles of terrain in pursuit of the men who left him for dead. Though he could read and write, Glass never set his story down in his own hand. It was first published by another writer in a Philadelphia journal in 1825. It may well have been embroidered then. It has been embroidered many times since.
The film has invented some extra obstacles for Glass: it is snowing throughout, even though in real life his trek took place between August and October; the Arikara track him and chase him into a tree; he has to hollow out a dead horse to make himself a sleeping bag. As for the ending, it has been changed in one significant way: in real life, nobody got killed.