History’s most famous feuding redheads got at it again in “Mary Queen of Scots,” an engrossing, marvelously-acted account of the monarchical cousins that suggests their real enemy wasn’t each other — it was the grasping, pushy and ambitious men who surrounded each in her own court.

It’s more historical than “history,” and as the history itself is Byzantine in its complexity, stage director turned filmmaker Josie Rourke is hard-pressed to keep it all moving and not cast the viewer adrift in the process.

But stars Saoirse Ronan and Margot Robbie give performances of such textured subtlety, full of tenderness, vulnerability, fire and steel, that even when it drags “Mary” drags us along with it.

Newly-widowed Mary returns to her native Scotland having just buried her husband, King Francis of France. She was Queen of Scotland when she left, her homeland now ruled by regents. Now she’s back, speaking French without an accent and ready to stake her claim to her throne and assert her place in the English throne’s line of succession.

But she’s Catholic. Her half-brother Lord Moray (James McCardle), one of those ruling in her stead, is Protestant. And the firebrand Presbyterian John Knox (David Tennant, fierce) is openly contemptuous of Mary and her ambitions.

“Are we to abide a Papist and a WOMAN?”

There’s trouble in court at Holyrood Castle. And that’s nothing to the turmoil that’s roiling London, 400 miles to the South.

It’s 1561, and her cousin Elizabeth (Robbie) is just getting her footing, ruling a once-Catholic land which her father Henry VIII turned officially Protestant, navigating the treacherous shoals of English, Papal and global politics as an unmarried woman just making up her mind that she would not marry.

“I choose to be a man,” she tells her most trusted advisor, Sir William Cecil (Guy Pearce, all conspiratorial whispers). But Cecil and other members of her Privy Council (Ian Hart, Adrian Lester) are alarmed by Mary’s presence, with her having a legitimate claim to Elizabeth’s throne as well as her own.

The two queens? They act as if they can work this out without any mansplaining or man meddling. Elizabeth is most concerned with self-preservation and protecting the monarchy. Mary suggests. “Name us heir,” using the regal “we/us” of course.

And Elizabeth, whatever concerns swirl around her about a renewal of Catholic-Protestant hostilities and her own legitimacy (Daddy divorced Mommy by lopping off her head), is willing to hear Mary out.

Maybe she’ll fix the unmarried Mary up with her own Protestant suitor, the Earl of Leicester, Robert Dudley (Joe Alwyn), the suggestion being that with a Protestant husband and consort (or even king), the dueling faiths will keep the peace.

Mary’s counter offer is “This is a matter of the heart, not the state.” And as she gets more worked up, she sets her sights on a marriage of her own choosing that will produce an heir.

“I will be the woman she is not!”

But this feud never descends into the cat-fight other films on the subject tend to turn it into. These are reasonable women, abiding by each other’s demands, with scheming menfolk behind them itchy to start a plot or pull the trigger.

A Stuart uncle (Brendan Coyle of “Downton Abbey) gets his handsome Catholic son, Lord Darnley (Jack Lowden) in front of Mary, and that’s all she wrote — and married.

Now the threat is real and the scheming — men trying to strong-arm each queen into action or usurp Mary’s power — reaches a peak.

As the film opens with Beheading Day in 1587, we know how this is going to play out.

I like the way “Queen of Scots” deviates from the usual manner of depicting Elizabeth I as victim of “two Marys,” sister “Bloody Mary” before she took the throne, “Mary Queen of Scots” after she ascended. Cate Blanchett’s “Elizabeth” movies repeat it. Elizabeth is almost helpless against the first Mary, cold-hearted and ruthless against the second — typically.

Robbie’s Elizabeth has a touch of the temperamental (the Elizabeth I cliche), but a broken sadness about her. No sex, please, Dudley. Can’t risk having an heir — legitimate or otherwise. Mary’s unbending resolve rattles her, and she blinks. Ravaged by “the pox,” she fears she’s lost another advantage over her rival — her looks.

Robbie is transformed in this performance, making Elizabeth lash out at her advisors and flinch at Mary’s every move — a strong woman hobbled by doubt. Her makeup, even before “the pox” is startling enough to make one question those “The screen’s next great beauty” labels of just a couple of years before. That took guts.

Ronan’s Mary is both feminine and in charge of her own destiny, lecturing her husband when invaders approach that “these swords are NOT just for show, you know.” And yet she is brought low, betrayed and undone, labeled “a whore and adulteress” by the power-drunk preacher Knox.

I love the way Rourke uses each queen’s ladies in waiting as a gang, rousting the impertinent men out of court when privacy is called for, protecting their queen when they can, distraught outside the door to each woman’s bedchambers when they cannot.

Color-blind casting puts Asians and men of color in high positions in each queen’s retinue, and political correctness has Mary refusing to blame a gay minstrel for sleeping with her gay husband, because it is “your nature” and he didn’t betray that.

And there’s the much-discussed “meeting” scene between the two queens, which never happened. 

No one had the termity to tell stage-director Rourke that she wasn’t adapting Shakespeare and such liberties are jarring when you’re dealing with history and not fiction.

Those are minor quibbles, though. More historical accuracy might have been achieved in the flat, uncinematic lighting scheme of this digital production. Go back to Blanchett’s “Elizabeth,” 20 years ago, if you want to see vibrant colors and faces that don’t look washed-out by flat lighting. This looks…primitive.

There’s grit and gloom to the combat and marching into combat scenes. But even the gorgeous Scottish scenery, backdrops for romantic walks and horsebacks, lacks the majesty and visual pop that shooting on celluloid might have given it.

Surprised there’s not a “Technicolor” app for that. Yet.

But none of those failings undoes “Mary Queen of Scots,” because the director took her own film’s themes to heart. In the end, she leaves it in the most-capable hands of her two leading ladies and they do not disappoint. The stars outshine the production.

MPAA Rating: R, graphic violence, sex and nudity.

Cast: Saoirse Ronan, Margot Robbie, Guy Pearce, Adrian Pierce, Ian Hart, Gemma Chan

Credits: Directed by Josie Rourke, script by Beau Willimon, based on John Guy’s “Queen of Scots: The True Life of Mary Stuart.” A Focus Features release.

Running time: 2:10