Which event marked the beginning of the civil war?

The Civil War was a war (although Congress never issued a Declaration of War) unleashed in the United States from 1861 to 1865. As a result of the historical controversy over slavery, the war broke out in April, 1861, when the Confederate forces attacked Fort Sumter in South Carolina, shortly after President Abraham Lincoln took office. The nationalists of the Union proclaimed loyalty to the Constitution of the United States. They clashed with secessionists from the Confederate States, who defended the rights of states to expand slavery.