American artist Winslow Homer began his career as a news artist for Harper's Weekly, sketching battles scenes and camp life. His initial drawings were of the camp, commanders, and troops of famous Union officer, Major General George B. McClellan, at the banks of the Potomac River in October of 1861.
On April 15, 1861, President Abraham Lincoln proclaimed a state of insurrection, three days after the first guns fired upon Fort Sumter. Lincoln carefully avoided the use of the word "war", which would have implied a clash with a foreign country, which would have help legitimize the claims of the Confederacy's claims to national sovereignty.
"Jackson is driving us mad. He don't say a word - no order, no hint of where we we're going."
~ Confederate Lieutenant General Richard S. Ewell,
Ewell was upset that General 'Stonewall' Jackson
kept his day-to-day plans secret from even his
I therefore tender my resignation, which I request you will recommend for acceptance. It would have been presented at once but for the struggle it has cost me to separate myself from a service to which I have devoted the best years of my life, and all the ability I possessed.
~ General Robert E. Lee,
in his official resignation letter from the U.S. Army to General Winfield Scott,
April 20, 1861