Slavery is America’s original sin, and sinners are slow to repent. At the University of Colorado, we hope to heed our better angels.

So it is that the university faces a sad episode in its history. This year, we observe the 100th anniversary of the graduation of Lucile Berkeley Buchanan, the first African American woman to earn a degree from CU. This occasion should have been a source of pride. It is not.

The daughter of slaves emancipated in Virginia, Buchanan was born in 1884 in Denver. When she graduated from CU in 1918, Buchanan’s mother, two sisters and a niece came to campus to watch. But she was not allowed to accept her diploma on the Macky Auditorium stage, as white graduates did. She is not pictured in the yearbook, as white alumni were.

Stung by the rejection, Buchanan left CU and vowed never to return. “She kept her promise,” writes Polly McLean, an associate professor of media studies in the CU Boulder College of Media, Communication and Information. McLean, who spent a decade researching Buchanan’s long-overlooked life, has written a biography of Buchanan.

The 13th Amendment raised hopes of equality for African Americans, but those hopes were repeatedly crushed. Reconstruction preceded the rise of the Ku Klux Klan, the barbarous Jim Crow South and the racism that haunts America five decades after LBJ signed the Civil Rights Act.

For Buchanan, this was not history. It was life. In 1899, racism drove Buchanan’s sister to suicide. In 1913, racists lynched a black man in Hot Springs, Ark., where Buchanan was a school teacher. And within seven years of Buchanan’s CU graduation, the Klan controlled Colorado’s government.

During Buchanan’s lifetime, CU never acknowledged her place in its history. It had ample time to do so. She lived to be 105 and suffered obscurity even in death. She was buried in an unmarked grave.

We cannot correct our historic sins, but we should admit them. Sometimes, we do. In 1993, a CU alumnus who learned of Buchanan’s fate arranged to have her grave more properly marked. And during commencement this May, CU Boulder Chancellor Philip P. DiStefano will officially recognize Buchanan’s place in university history.

These gestures are symbolic, but symbols matter. However meager and tardy, the university’s recognition is a kind of reparation. We remember Lucile Berkeley Buchanan not only to honor her life, but also to reflect on what we once did and what we could now learn.

It is not enough to tout our historic good deeds—when Abraham Lincoln condemned slavery or when CU President George Norlin defied the Klan. Intellectual honesty demands that we acknowledge the full range of our former selves. The author Ta-Nehisi Coates cogently makes just this argument:

“We invoke the words of Jefferson and Lincoln because they say something about our legacy and our traditions. We do this because we recognize our links to the past—at least when they flatter us. But black history does not flatter American democracy; it chastens it.”

Chastened by history, let us strive to do better.

James W.C. White is interim dean at the College of Arts and Sciences.