When the Civil War started, there were many free blacks in the North. These men volunteered to fight for the Union army. At first, President Abraham Lincoln did not want to recruit black soldiers. He did not want to upset people in the border states between the South and the North. He also did not want to anger people in the North who did not want to fight a war over slavery. He insisted the North was fighting the war to save the Union.
Blacks were disappointed, but they didn't stop trying. Through 1861 and most of 1862, they pushed to be allowed in the army. Even if Lincoln did not want to say it, most blacks knew this was a war against slavery. The North continued to not allow black soldiers to fight with the army. But in the South, slaves were being forced to help in many different ways. They had to build forts and work as nurses.
As the war progressed, the Union had to decide what to do with escaped slaves. When the Union army went near a plantation, many slaves escaped and crossed over to the Union side. Some thought the slaves should be sent back. Others wanted to put them to work helping the Union army. Finally, escaped slaves were declared "contraband of war." A slave could earn this title if he had been forced to help the Confederates in any way. If a slave was found to be contraband, he was declared to be free.