What historical events influenced the Harlem Renaissance?

Several events caused the Harlem Renaissance, a period when black arts and the black community flourished in the Harlem neighborhood of Manhattan in the 1920s and early 1930s, until the effects of the Great Depression impoverished the area. 

In the South, by 1900, blacks saw the gains they had achieved during the Reconstruction era eroded as white Democrats increasingly took political control and used voting laws, lynching and other means of terror to disenfranchise the black population. As a result, many blacks began to think about migrating north. When World War I started, this gave a great boost to black migration, because immigration from Europe dried up (most of the men there being conscripted into the army or into the war efforts in their home countries) just at the moment factories were going into high gear in the United States to supply the war demand. Therefore, blacks found it easy during this period to migrate north because jobs were plentiful. Many showed up in Harlem, which also attracted blacks from the Caribbean. Black leaders like W.E.B Dubois encouraged black artists to move to Harlem. Naturally, as it became a cultural center, more and more artists arrived. In this period too, the famed Abyssinian Baptist Church of Harlem, under Clayton Powell Sr, became a center of black cultural life. And as the economy boomed after World War I across the United States, some whites invested capital in the vibrant and expanding Harlem arts scene. In a nutshell, it was the economic opportunities opened up to blacks by both the first World War and the subsequent postwar economic expansion that allowed the Harlem Renaissance to occur. 

What historical factors influenced the Harlem Renaissance writers?

As with many movements in the arts, the Harlem Renaissance was influenced heavily by the economics of its time. During the early 20th century, America like much of the world was moving from an agriculturally based economy to a more industrial. Cities in the North were leading the way in this change, so many African Americans in the less affluent South started to seek higher paying jobs above the Mason Dixon line. 

U.S. policy on immigration also prompted this northern migration, as the government began limiting the numbers of immigrants from entering the country. This policy along with the industrialization above and a promise of a better more equal life caused African American populations in major northern cities to nearly double by the 1930s.

Socially, writers such as Booker T. Washington had pushed the notion forward of a well educated and proud African American man instead of the backward stereotypes that many people, including African Americans, had accepted from their society. This push towards independent thinking and pride in leadership of new lives also helped the Harlem Renaissance blossom.

Beyond the extensive reach of WWI general influence, the end of the war in 1919 also brought racial relations to a head. White soldiers returned and struggled to accept the changing roles of African Americans. African American soldiers returned from fighting the respect they earned on the battlefield and once again were treated as second class citizens by fellow Americans they defended. In 1919, 25 race riots took place and over 75 lynchings were reported.

Finally, Harlem itself influenced the movement as it became the center of African American life and culture in the northeast. The neighborhood had once been a wealthy white collection of homes and recently experienced a housing bubble and it was left with foreclosed properties that were affordable. The comfort and excitement offered by the neighborhood continued to attract African American leaders in all walks of life through the 1920s. The population quadrupled in that decade.