Because they had declared South Carolina to be part of the Confederate States of America, and they were not willing to allow a Union garrison on an island fort in Charleston Harbour.
April 12 1861 to April 13 1861 is the dates that Fort Sumter was under fire
1861
Confederates attacked Fort Sumter in 1861.
At 4,20 AM 0f April 12, 1861.
Lincoln's decision to break the siege forced the confederates to fire on the fort.
The transport was attempting to take supplies to Fort Sumter.
The Confederates commandeered the fort and fought there
The Confederates commandeered the fort and fought there
Confederates
April 12, 1861 when the Confederates opened fire on Fort Sumter.
At Fort Sumter in the harbor at Charleston SC.
the confederates won