Did you know that Vincent van Gogh’s status as an art world giant owes a big thanks to the efforts of one woman? As Hans Luijten, senior researcher at Amsterdam’s Van Gogh Museum, writes in a new biography, van Gogh's sister-in-law, Jo van Gogh-Bonger almost singlehandedly ensured the artist’s legacy, assuming full responsibility for promoting his work upon the death of her husband, Theo, in 1891.

“Bonger was a force to be reckoned with,” Luijten tells the Art Newspaper’s Martin Bailey, “and we are now able to tell her life story in great detail.”

Luijten’s biography, titled Everything for Vincent: The Life of Jo van Gogh-Bonger, debuted at the Van Gogh Museum this week. Per Bailey, the 620-page book is currently available in Dutch, with an English translation expected to follow next year. Representing the culmination of more than 10 years of research, according to de Volkskrant’s Michiel Kruijt, Everything for Vincent is poised to become the definitive biography of this largely unheralded character.

Bonger, born to a middle-class Dutch family in October 1862, was working as an English teacher when Theo, reportedly struck by love at first sight, asked her to marry him. Theo may have been smitten, but as Artsy’s Sarah Bochicchio writes, Bonger did not share the younger van Gogh’s ardent feelings: “I couldn’t say ‘yes’ to something like that,” she wrote in her diary following the 1887 proposal. “... Oh, if only I could, why does my heart feel nothing for him!”

Despite her initial reluctance, Bonger agreed to continue corresponding with Theo. He eventually won her over, and in 1889, the pair officially wed. Less than a year later, Bonger gave birth to the couple’s only child, a son named Vincent Willem in honor of Theo’s beloved older brother.

Writing for de Volkskrant, Kruijit notes that van Gogh experienced extreme mental health issues in the months surrounding his brother’s wedding. In December 1888, the artist sliced off his own ear in a fit of frenzy, and shortly after the ceremony itself, he attempted suicide. Although Theo believed van Gogh’s condition was improving by the spring of 1890, his hopes were soon thwarted: On July 27, the painter shot himself with a revolver. He died two days later with Theo at his bedside.

According to the Van Gogh Museum, a heartbroken Theo made it his life’s mission to preserve and promote his brother’s oeuvre. Unfortunately, he had very little time to accomplish this task. Just six months after van Gogh’s death, Theo followed him to the grave, succumbing to the effects of syphilis at age 33. Bonger, then 28 years old, was left to take care of both the couple’s newborn son and her husband’s barely started campaign.

In a diary entry written several months after Theo’s passing, Bonger reflected on the weighty work that lay ahead: “He has left me another task—Vincent’s work—getting it seen and appreciated as much as possible.” Although she acknowledged she was “not without purpose,” the young widow added, “I do feel lonely and abandoned—all the same, there are moments of great serenity—that the satisfaction of my work gives me.”

Per Artsy’s Bochicchio, Bonger refused to simply sell van Gogh’s portfolio and move on with her life. Instead, she moved to Bussum, a small Dutch town with a surprisingly vibrant artistic community, and started organizing exhibitions of her brother-in-law’s works. By 1900, Bonger had coordinated around 20 successful shows across Holland; next, she turned her attention to the wider art world, collaborating with art dealers, artists and museums to publicize van Gogh’s creations. By her death at age 62 in 1925, Bailey notes for the Art Newspaper, Bonger had spearheaded a major Stedelijk Museum retrospective featuring nearly 500 paintings and drawings, sold around 250 original van Goghs, and published the artist’s extensive letters.

Outside of her efforts to promote van Gogh’s legacy, Bonger becme engaged in the political sphere. During a visit to New York in 1917, she attended a meeting led by communist leader Leon Trotsky, and in 1905, she co-founded the Amsterdam Social-Democratic Women’s Propaganda Club. Her obituary, published in De Proletarische Vrouw in September 1925, stated: “She always apologized for not being more active in the [socialist] movement. She would say that bringing her son up properly was also a good thing to do for society. ‘So that has been my main work.’”

Van Gogh’s namesake, Vincent Willem, continued his mother’s work in the decades following her death. The Van Gogh Museum, established by the younger Vincent to ensure his uncle’s art would remain accessible to the public indefinitely, opened its doors on June 3, 1973.