The Smithsonian's National Portrait Gallery is opening two new exhibits that retrace the history of the Civil War, including a display of lesser known portraits by photographer Mathew Brady.

One exhibit opening Friday, "Mathew Brady's Photographs of Union Generals," will feature Brady's portraits of the ever-changing roster of Union army generals. It includes images of many of the North's military leaders, including George McClellan, Ambrose Burnside, William Tecumseh Sherman and Ulysses Grant.

Another exhibit will feature the Confederate cause. "The Confederate Sketches of Adalbert Volck" will include the pictorial propaganda created by a Baltimore dentist who sided with the South. His work focused on vilifying President Abraham Lincoln, Union soldiers and northern abolitionists.

The Brady photographs are on view through May 2015. The Volck sketches are on view through January.