school heard about Isabel’s ancestry, she was expelled.

Her family sued. The court ruled, however, that the existence of black ancestors, no matter how distant, was enough. “The child is of Negro blood,” the judge concluded. “Her racial status is that of the Negro.” Washington was then in the midst of some of the darkest years of racial segregation and discrimination. As enslaved people on local farms, black people had been in Washington before it was Washington and were present as the city and institution of slavery evolved.

In the late 1700s and early 1800s, slaves hired out by their masters helped build the US Capitol and the White House, and sometimes were allowed to keep a little of the money they earned for their owners. But the horrors ofslavery were there for all to see. The local jail served as a kind of holding pen for slaves and kidnapped free blacks headed elsewhere, according to historian Constance McLaughlin Green in her 1967 book The Secret City: A History of Race Relations in the Nation’s Capital.

One observer wrote of watching from a door of the Capitol as a slave coffle passed, “men, women and children ... bound together in pairs, some with ropes, and some with iron chains”.

In 1849, a little-known congressman from Illinois named Abraham Lincoln introduced a bill calling for the abolition of slavery in the District. The bill never passed. And it wasn’t until 1862, when Lincoln was president, that Congress enacted a law freeing the 3,100 slaves owned by Washington’s residents. After the