We knew some of the First Lady's ancestors were slaves. But the New York Times' detailed genealogical investigation into precisely who those slaves were brings into moving relief what an astonishing historical earthquake her presence in the White House is.

The big news in the Times piece is that Michelle Obama's great-great-great-grandmother, Melvinia Shields—a slave girl in South Carolina and later Georgia who survived to see freedom after the Civil War—bore three children, including Obama's great-great-grandfather, by a white man. It's not clear who, but the Times suggests that the father could have been Melvinia's owner, Henry Shields. And at least one child listed in a census as "mulatto" was born to Melvinia after emancipation, suggesting that their liason (whether coerced or consensual) outlasted her enslavement.

But Michelle Obama's ancestry isn't really the point: It's that the distant monumental evil that lives in history books can be tangibly connected to her, and to see the actual lives of her ancestors who lived with slavery and its consequences recounted with texture and detail is all the more moving because it is so rarely done. It's of course obvious that most African-Americans have similar genealogical trails, and there is no shortage of historical narratives about slavery and the Jim Crow South. But as Henry Louis Gates has pointed out with his genealogical research, one of slavery's many subsidiary crimes is the extent to which is has denied its inheritors a detailed sense of family history and mythology. It stands as a roadblock to the past. Family trees are fuzzy and uncertain; deeds of sale, when they can be found, don't contain as much information as birth certificates. Even with the resources of the Times and a genealogist it consulted, we still don't know for sure who the father of Melvinia Shields' children was.

So Michelle Obama had no idea who Dolphus Shields, her great-great-grandfather and Melvinia's son, was. Born into slavery in 1859, he settled in Birmingham, Alabama, became a co-founder of a Baptist church there, started a hardware store in the white part of town, owned his own home, and carried around candies to hand out to the children. "There was no smoking, no cursing, no gum chewing, no lipstick or trousers for ladies and absolutely no blues on the radio, which was reserved for hymns," in his house, the Times reports, and he went to church nearly every night of the week.

Dolphus died in 1950, just 14 years before the birth of his great-great-granddaughter. Yet she didn't know that he existed, and it took the efforts of a newspaper to inform her, via the front page, of such an intimate part of her own life and past. The historical blind spot may have been in part self-inflicted:

As for his ancestry, Dolphus Shields didn't talk about it.

"We got to the place where we didn't want anybody to know we knew slaves; people didn't want to talk about that," said Mrs. Heath, who said she assumed he had white relatives because his skin color and hair texture "told you he had to be near white."

Maybe that reticence carried forward to his subsequent generations, and maybe that explains how it can be that the First Lady of the United States never learned anything about Dolphus. (Maybe it also explains why she declined to comment for the Times story at all.) Which is why the Times' unraveling of that history is so moving—the lack of solid information, compounded by that sense of shame harbored by people of Dolphus' generation, has obscured that sense of rooted American-ness for so long. Reading it, we couldn't help but think of WASPs who trace their ancestry back to the Mayflower, and that Michelle Obama should be just as proud.

(Our night editor, you may have read, disagrees.)

[Photo via the Virginia Foundation for the Humanities and the University of Virginia Library.]