established an identity in Philadelphia during the 20th century was the gay community. The city's homosexual community is centered in a portion of Washington Square West, nicknamed the "gayborhood" by residents. African Americans The first black people in Philadelphia were slaves; with at most 1,500 people living as slaves in the city during the period slavery was legal. Slaves in Philadelphia usually lived in the same house of their owners and worked as servants or in their owners' shops. An abolition law in 1780 did not free any existing slaves, but banned the slave trade in Pennsylvania and freed the children of slaves born after the law was passed once they reached a certain age. By the time the law was passed, about 400 slaves and 800 free black people lived in Philadelphia. Many newly freed slaves and escaped slaves from the South moved to the city, and by 1820 the city's African American population was nearly eleven percent. During this time one former slave, Richard Allen, founded the African Methodist Episcopal Church in Philadelphia. As the African American population grew, so did white hostility towards them. African Americans were attacked and killed in the street and in their houses during a race riot in 1834, and four years later a state law was passed that prevented African Americans from voting. Abolitionists were also targets; they were prevented from spreading their message, and one of their meeting houses was burned. In the latter half of the 19th century and the first half of the 20th century large numbers of African Americans migrated from the Southern United States to Philadelphia giving the city the largest African American population of a northern U.S. city. In 1896 W. E. B. Du Bois came to Philadelphia and wrote his sociological book The Philadelphia Negro. Du Bois' study of the city's African Americans found many lived in Center City with growing populations in West Philadelphia. Many African Americans lived in neighborhoods near the rich white families they worked for. There was also a small group of upper class African Americans, both educated, wealthy and Philadelphia born, who descended from freedmen earlier in the century. The aristocratic African Americans were generally isolated, not recognized or even known about by the white population and alienated from the rest of the city's African American population. As Philadelphia grew more industrialized the new factories refused to hire African Americans,