“She was the only woman in the world worth dying for.” It was these words, which I came across in a reference to Fanny Van de Grift Stevenson, that first caught my attention. They were written by an admirer, not the man she devoted her life to—her famous husband, Robert Louis Stevenson.

But Louis, as he was called, actually did risk his life to get to her, crossing the world when he was in ill health, because he felt he could not live without her. “Honour, anger, valour, fire” were qualities he attributed to Fanny, who sustained him with “a love that life could never tire, evil quench, nor death stir,” as he wrote in one poem. As I delved deeper into their story, I came to realize that, without Fanny, there would be no Robert Louis Stevenson as we know him.

He probably would not have written or finished , and might well have been a different story from the one the world knows today. Without Fanny, Louis probably would not have become one of the most famous and beloved authors in the world. Theirs was an unlikely Victorian love story: He was a university-educated writer from a prominent family in Scotland; she was a high school graduate from the rustic Midwest.

He was ambitious but in frail health and adrift, penning magazine essays that would likely be forgotten. She was forceful and determined—whether she was seeking her fortune in the Nevada silver rush or studying art in Paris. She was ten years his senior and married, with children, when they met.

How coul.