When did Harlem New York become a black neighborhood?

In the nineteenth century, the district known as Harlem in northern Manhattan was a fashionable white residential district, a favorite site for summer homes.

Apartment buildings rose in the boom of the 1880s.

After the panic of 1893, however, many buildings became vacant, and property owners began renting to blacks.

By World War I, much of Harlem had become black.

But as late as the 1930s, blacks were kept out of some parts of the neighborhood.