When South Carolina Seceded in 1860, the spirit of rebellion engulfed the state and thousands of volunteers and Militia gathered in Charleston ready to fight. The only Union presence was a force of 85 men at Fort Moultrie, adjacent to Charleston Harbor where better defenses were in place.
Major Anderson took his Union troops from Fort Moultrie to For Sumter, believing the move would reduce tension. Southerners saw this as an act of aggression. Fort Sumter had only six weeks of rationing left. Lincoln chose to resupply his men. He notified the Confederates.
The Confederates opened fire upon Fort Sumter on April 12, 1861 and 33 hours later the fort surrendered. On April 15 Lincoln called for 75,000 men to quell the "Southern Insurrection". The Great Civil War had begun.