What one major primary document from the Civil War?

One major primary document from the Civil War is the Emancipation Proclamation, issued by President Abraham Lincoln on January 1, 1863. This executive order declared the freedom of all enslaved people in Confederate-held territory, fundamentally transforming the war's purpose by linking the fight to the issue of slavery. It also allowed for the enlistment of African American soldiers in the Union Army, further altering the dynamics of the conflict. The Proclamation remains a pivotal symbol of the struggle for freedom and equality in American history.