Edwin Vose Sumner was a career United States Army officer who became a Union Army general and the oldest field commander of any Army Corps on either side during the American Civil War. His nicknames "Bull" or "Bull Head" came both from his great booming voice and a legend that a musket ball once bounced off his head.

The Peninsula campaign of the American Civil War was a major Union operation launched in southeastern Virginia from March to July 1862, the first large-scale offensive in the Eastern Theater. The operation, commanded by Major General George B. McClellan, was an amphibious turning movement against the Confederate States Army in Northern Virginia, intended to capture the Confederate capital of Richmond. McClellan was initially successful against the equally cautious General Joseph E. Johnston, but the emergence of the more aggressive General Robert E. Lee turned the subsequent Seven Days Battles into a humiliating Union defeat.