Signe Pike loves legends and myths, but it’s not enough for her to learn the stories. She also wants to understand where they came from. She’s always wondering “is there any particle of truth behind a legend?” she says. Surprisingly often it turns out there is one: the legend of the unicorn, for example, arose from sailors returning home with narwhal tusks.

So when Pike stumbled across Adam Ardrey’s Finding Merlin in a Glastonbury bookshop, she was riveted by his theory that Merlin was based on a sixth-century Scottish scholar and warrior known as Lailoken. Even more intriguing was the fact that Lailoken had a twin sister, Languoreth, an important historical queen who had been all but forgotten while her brother became a figure of myth.

Pike started to search for mentions of Languoreth in the historical record. They were few and far between, but Pike slowly managed to piece together the basics of the queen’s biography, which formed the basis for The Lost Queen. The first in a trilogy, the novel recounts Languoreth’s childhood, her marriage, and her attempts to bridge the growing gap between those who followed the traditional ways and the ever more powerful Christians.

Early in her research, Pike realized that Languoreth had been raised in the old Celtic religion but married to a Christian king. “It definitely speaks of alliance and it speaks of having to compromise and sacrifice some of your beliefs for the beliefs of the person you’re partnered with,” Pike says, “and I started to wonder how that makes you grow as a person.”

Yet as central as Languoreth’s marriage is to her story, she’s mainly remembered as an adulteress. According to an old Glasgow legend, she gave her husband’s ring to a passing knight, who promptly lost it in the river. It’s later discovered in the belly of a fish. There are many different versions of this story, and in some the husband is actually the person who throws the ring in the river, but it’s a paltry remembrance for a woman who wielded considerable power in her own time. Nonetheless, Pike says, “I really wanted to get more into her heart and we’ve all had moments where we were with one person and felt feelings for another.” In The Lost Queen, she expands this rather silly story into a deep and tragic love story.

“Life is difficult and life is painful. Life isn’t about easy choices and all happy endings,” Pike says. “I think that’s what resonated with me.” As chaotic as Languoreth’s era was, Pike’s retelling centers on the ancient queen’s choices and finds joy in the powerful connections she forms.

Though she’d written nonfiction in the past, Pike decided the only way to do Languoreth’s life justice was in novel form. As much as she enjoys putting herself in the shoes of people from the past, she acknowledges that it can be difficult for many to imagine such a radically different time. “Really the only way to resurrect Langoureth was to do it via story because that was the only way you were going to really truly be able to reach enough people, to captivate them, to get them to realize what an amazing woman she really was,” Pike says.

It’s important to Pike that readers recognize the story is historical fiction—most of what she describes really did happen, even if no one is quite sure how. As a queen in sixth-century Scotland, Languoreth endured challenges most of us struggle to imagine and she survived. “For people to say that it’s made up,” Pike says, “is to me the biggest insult to her and her memory.”

Alex Heimbach is a writer and editor in California. Full disclosure: Signe Pike is related to Kirkus Reviews' nonfiction editor, Eric Liebetrau.