“I early conceived a liking for, and sought every opportunity to be in a position to relieve the sufferings of others.” So wrote Rebecca Lee Crumpler in A Book of Medical Discourses in Two Parts. When it was published in 1883, it was one of the few medical texts written by an African American. But the author could claim an even more rarefied accomplishment—150 years ago, she was the first black woman to receive a medical degree in the United States.

When Crumpler enrolled in New England Female Medical College in 1860, there were some 54,543 physicians in the United States. Only 300 of them were women, and none were African American. In 1864, a week after Crumpler completed her final oral examinations, she was named “Doctress of Medicine.”

Crumpler was born in Delaware in 1831, and she was raised in Pennsylvania by an aunt known for taking care of sick neighbors. Inspired by her aunt’s compassion, Crumpler became a nurse after moving to Charlestown, Mass., in 1852. The doctors with whom Crumpler worked wrote letters supporting her entry into the world’s first women’s medical school.

Upon graduation, Crumpler initially practiced in Boston. But “desiring a larger scope,” as she wrote in her book, she decamped for an unknown location in “The British Dominion” (possibly Canada), focusing on poor women and children. After she returned to the States at the end of the Civil War, Crumpler settled in Richmond, Va., to perform “real missionary work,” tending to former slaves who lacked access to medical care.

Unsurprisingly, African American physicians in the South were not well received. In fact, “some people wisecracked that the M.D. behind [Crumpler’s] name stood for nothing more than ‘Mule Driver,’” reported a 1964 Ebony magazine article.

By 1869, Crumpler had returned to Boston, “receiving children in the house for treatment; regardless, in a measure, of remuneration,” she wrote. She also continued taking notes for her journal, which ultimately became A Book of Medical Discourses; it featured chapters and sections as varied as “Nursing From the Breast Made Easy” and “Brain Fever.” Much of the text focused on practical applications, reflecting Crumpler’s desire to help individuals combat their own illnesses. “People seem to forget that there is a cause for every ailment, and that it may be in their power to remove it,” Crumpler wrote.

Her example notwithstanding, the number of African American women in medical school is in decline, from 4.5% of students in 2002 to 3.8% in 2011.