At the outbreak of the Civil War, Irish citizens on both sides of the Mason-Dixon answered the call to arms. This was most evident at the Battle of Gettysburg.

Louisiana Irish Rebels charged with the cry "We are the Louisiana Tigers!" Irish soldiers of the Alabama Brigade and the Texas Brigade launched assaults on the line's southern end at Little Round Top. During Pickett's Charge, Gaelic brothers fought each other as determined Irishmen of the Sixty-Ninth Pennsylvania Volunteer Infantry repelled Irish of the Virginia Brigade in one of the most decisive moments in American history. Author Phillip Thomas Tucker reveals the compelling story.