Dennis Frye, author and chief historian at Harpers Ferry National Historic Park, talks about the state of the war in early September 1862. Confederate General Robert E. Lee was poised to invade the North, causing alarm among northern government officials and citizens. General Lee’s goal was Pennsylvania, but by what route and through what cities and towns was unclear. Mr. Frye spoke for about 45 minutes at the Frederick Visitor Center in Frederick, Maryland.