Short answers, pulled from the story.
The first major land battle of the American Civil War erupted on the 21st of July 1861 near Manassas Junction. Brigadier General Irvin McDowell led a Union army toward Richmond with confidence that victory would be swift and easy. Confederate forces routed his troops in an embarrassing defeat that shattered Northern illusions about the war's duration.
Kentucky held strategic importance due to its control over the Tennessee and Ohio rivers. On the 3rd of September 1861, Confederate General Leonidas Polk occupied Columbus, Kentucky, violating state neutrality. This violation enraged citizens and caused the state legislature to request federal assistance.
The Battle of Antietam ended Robert E. Lee's invasion of the North and allowed President Lincoln to announce his preliminary Emancipation Proclamation one hundred days later. The proclamation effectively prevented Britain from extending diplomatic recognition to the Confederacy. France supporting the Confederacy remained a possibility but never came to pass.
European investors gave the Confederacy approximately a 42 percent chance of victory prior to these battles before news led to a sell-off in Confederate bonds. By the end of 1863, the probability of a Southern victory fell to about 15 percent in the bond market. Southern morale deteriorated substantially following these victories, creating a perception among Confederate forces that the coil was tightening around them.
Following the victory at Chattanooga, Grant was appointed general-in-chief of all Union armies on the 12th of March 1844. He moved his headquarters east to Virginia while leaving Sherman in command of forces in the Western Theater. Grant devised a coordinated strategy that would strike at the Confederacy from multiple directions.