On Tuesday, to mark the 150-year anniversary of the start of the Civil War, we aired a segment featuring two African-American men whose ancestors fought with the confederate army. Nelson Winbush and Stan Armstrong said they  are proud of their relatives' military service.  But to some of our listeners  the segment smacked of misinformation. Did African-Americans fight in the Confederate Army in the Civil War? And if so, did they do so out of free will or as enslaved people? Jim Hart from Baltimore wrote in to say, "There is no historical evidence of actual black soldiers (as opposed to slave laborers and slaves accompanying their masters) in Confederate service, prior to a desperate attempt in the last month of the war to enlist some slaves with the permission of their masters."  Atlantic Senior Editor Ta-Nehisi Coates  also challenged our segment  on his blog.   Did Black men serve on the side of the confederate army? Many experts don't agree on the answer to that question.  For more perspective, we turn to Kevin  Levin.  He  is chair of the history department at  St Anne's - Belfield School  in Charlottesville, Virginia. He writes the blog  Civil War Memory,  and is author of the forthcoming book "Remembering War as Murder: Battle of the Crater." Levin is currently researching another book "Searching for Black Confederates in History and Memory."