For Alicia Vikander, playing Katherine Parr, the last of Henry VIII’s six wives in the opulent costume drama “Firebrand,” is about reclaiming women’s place in history.

Adapted from “Queen’s Gambit,” a bestselling historical fiction, “Firebrand” sees the Queen as a revolutionary, supporting radicals who would like to overthrow her scary husband’s Tudor throne. That means she is in danger, like two of Henry’s previous wives, of losing her head.

Henry (Jude Law) is not only paranoid and doomed by the open ulcer on his leg which will eventually kill him, he’s a moody tyrant and sexual bully whose lovemaking resembles rape.

“When Jude and I started to play the scenes,” Vikander, 35, began, “we knew we had to focus on the story about this marriage, to make it intimate and find the domestic feeling for this drama.

“That’s when you realize the kind of work, the intelligence and sheer determination she mustered to being able to outlive this thing.

“Actually having to for years create a relationship that she, in one way, needs to justify as real and feel like she has a purpose.  At the same time tiptoeing around a kind of time bomb of someone who can crack at any time.

“She had to live with this everyday fear of her life.”

The Swedish Vikander, an Oscar winner for the true-life 2015 trans drama “The Danish Girl,” did extensive research with eye-opening results.

Parr, she noted, “was the first ever woman in British history to be published under her own name. When I read her, it struck me that I was trying to figure out what the oldest text I had read before from a woman came from — and realized that that doesn’t go very far back in time. Most texts that we’ve been introduced to are done by men.

“To then have a text that is 500 years old” – Parr was 36, married to her fourth husband, when she died in childbirth in 1548 –”and gets as close as you do when you can read someone’s own words, that was truly quite remarkable to be able to have that connection.”

Period pieces have been good to Vikander, like “The Green Knight,” “A Royal Affair” and “Anna Karenina.”

Yet, she makes clear, “I’ve never made a decision to make a period drama because it’s a period drama. It’s always been down to me wanting to inhabit a certain character.

“Or in this case, it was very much the people involved. I was extremely intrigued seeing what Jude was going to do playing Henry, especially at this time near the end, the last few months of his life.”

“Firebrand” opens June 14