During and even immediately after the Civil War, very few American artists undertook direct representations of the catastrophic conflict or of the experience of the enslaved African Americans whose plight it decided. One of the most remarkable exceptions is this painting by the leading mid-century figure painter Eastman Johnson, who claimed to have based the subject on an actual event he had witnessed near the Manassas, Virginia, battlefield on March 2, 1862, just days before the Confederate stronghold was ceded to Union forces. In this powerfully simplified composition, a family of fugitive slaves charges for the safety of Union lines in the dull light of dawn. The absence of white figures in this liberation subject makes it virtually unique in American art of the period—these African Americans are the independent agents of their own freedom. (source)
More political art.