Events and battles
After Fort Sumter had fallen to the Confederacy, Lincoln called for 75,000 volunteers for 90 days to put down the rebellion.
Lincoln did this on April 15, 1861, and almost immediately four more states joined the Confederacy: Virginia, North Carolina, Tennessee, and Arkansas.
The remaining border states: Missouri, Kentucky, Maryland, and Delaware decided to stay with the Union. The nation was ready for war.
Fort Sumter to Manassas
Monitor and Merrimac
Battle of Fredericksburg