On 12 April 2011, the U.S. Postal Service begins a series commemorating the 150th anniversary of the Civil War, joining others across the country in paying tribute to the American experience during the tumultuous years from 1861 to 1865.
Two stamp designs will be issued each year through 2015. For 2011, one stamp depicts the beginning of the war in April 1861 at Fort Sumter, South Carolina (right stamp on the cover), while the other depicts the first major battle of the war three months later at Bull Run, near Manassas, Virginia (Left stamp).
To make up for the postage, Peterson used a 10c definitive stamp from the "American Design" series.