As the business capital of the nation, New York City had not welcomed the onset of the Civil War, as it meant losing the South as a trading partner.
Cotton was an extremely valuable product for New York’s merchants: Before the Civil War, cotton represented 40 percent of all the goods shipped out of the city’s port. And long after the slave trade was made illegal in 1808, the city’s illicit slave market thrived.
When the war broke out in 1861, there was even talk of New York seceding from the Union itself, so entwined were the city’s business interests with the Confederate States.

As the war progressed, New York’s anti-war politicians and newspapers kept warning its working-class white citizens, many of them Irish or German immigrants, that emancipation would mean their replacement in the labor force by thousands of freed enslaved people from the South.
In September 1862, President Abraham Lincoln announced the Emancipation Proclamation (which would take effect early the following year), confirming the workers’ worst fears.

At the time, Lincoln’s decision for emancipation sparked protests among workers in the city, as well as soldiers and officers in New York regiments who had signed up to preserve the Union, not to abolish slavery.