The Confederate States of America (CSA), commonly referred to as the Confederacy, was a secessionist state that existed from 1861 to 1865. The CSA was composed of 11 Southern states that declared their secession from the United States following the election of Abraham Lincoln to the presidency in 1860.
The Confederacy was considered a threat to the union because it sought to preserve the institution of slavery, which was seen by many in the North as an affront to human rights and a violation of the principles of the Declaration of Independence. The Confederacy's secession and the subsequent outbreak of the American Civil War were seen as an attempt to break up the United States and establish a new nation based on the principles of states' rights and white supremacy.
The Confederacy's military forces were led by General Robert E. Lee and General Thomas J. "Stonewall" Jackson, and they initially achieved significant successes in the early years of the war. However, the Union eventually gained the upper hand and defeated the Confederacy in 1865, thus preserving the union of the United States.