In the early twentieth century a real-estate slump left many Harlem buildings empty just as Black families were leaving the rural South and crowded districts elsewhere in the city. Black real-estate entrepreneurs such as Philip A. Payton Jr., who founded the Afro-American Realty Company in 1904, helped open blocks to Black tenants and buyers.
Migrants also came from the Caribbean, and Harlem became one of the most important Black urban communities in the world. In 1919 the 369th Infantry, the “Harlem Hellfighters”, marched up Fifth Avenue to a hero’s welcome after serving in the First World War.