In the opening pages of John Guy’s 2004 biography Queen of Scots: The True Life of Mary Stuart, he notes that she only learned to speak English during her final years in prison: “She spoke in French because this and Lowland Scots were her native tongues.” The film adaptation of Guy’s book, Mary Queen of Scots, directed by Josie Rourke, changes this, among other things. It stars Saoirse Ronan as Mary and Margot Robbie as Queen Elizabeth I. Both versions portray how Protestant members of Elizabeth’s court worked to keep the Catholic Mary from succeeding to the English throne, culminating in Mary’s execution at 44.

Our reviewer writes that “Guy’s account has all the twists and turns of a good thriller—and plenty of horror, too.” But much of Mary’s life is omitted from the film; for example, Guy points out that she once witnessed a boat accident in which several sailors died, that she almost perished in a fire, and that she was the object of an unbalanced poet’s obsession. None of these events are in the movie. Instead, there are numerous scenes of Mary lounging about with her courtiers—although their costumes, it must be said, are dazzling. The film also omits her first marriage, which left her a teenage widow, and many of her final years.

It offers some new additions, as well. There’s nothing in Guy’s book that indicates that Mary and Elizabeth were ever in each other’s presence, but the movie slyly creates a secret meeting between them—one that wouldn’t be in the historical record. This intriguing strategy extends to the most interesting creative choice in the film—portraying Mary’s second husband, Lord Darnley, as bisexual, and her Italian private secretary, David Rizzio, as gay. As the movie tells it, Darnley and Rizzo had at least one drunken one-night stand together. Again, there’s no solid evidence for this; Guy only notes that one of Darnley’s enemies claimed that the lord and Rizzio “would lie sometime in the same bed together.” Screenwriter Beau Willimon (creator of the Netflix TV series House of Cards) makes this event a reality, which effectively adds to the tragedy later on, when Rizzio is executed on suspicion of having an affair with Mary; Darnley signs Rizzio’s death warrant, despite knowing that the courtier is innocent. The film’s choice of a diverse cast is also refreshing. Gemma Chan, a British actor of Chinese descent, plays Bess of Hardwick, a white noble of Elizabeth’s court; Adrian Lester, a black British actor, plays the white Lord Randolph; and Puerto Rican actor Ismael Cruz Córdova plays Rizzio.

Despite all of these choices, though, the film feels formless and dull—partly because Mary’s enemies never come into sharp focus, as they do in Guy’s biography. It’s disappointing, for example, that the filmmakers didn’t do more with the fanatical Scottish minister John Knox, who famously wrote a diatribe against female rulers titled The First Blast of the Trumpet Against the Monstrous Regiment of Women. In the book, he comes across as a direct threat; in the film, he only gets one major set-piece—brilliantly performed by David Tennant—before drifting out of the story. The movie also omits the fact that many members of Mary’s Catholic court were terrified of being beaten up by roving “gangs of Edinburgh Calvinists.”

The film does have its moments, however; Rizzio’s murder scene is truly horrifying, and Robbie’s layered portrayal of Elizabeth is notable. However, if one wants to watch a fast-and-loose depiction of the life of Mary, Queen of Scots, there are more entertaining options. The CW television show Reign, for example, features all of the same characters—as well as Nostradamus and a human-sacrifice cult.

David Rapp is the senior Indie editor.