In Chapter 17 Gavin refers, hypothetically, to "some dedicated enthusiast panting for martyrdom in the simple name of Man" whom Flem could get to "shoot old Will some night" (302). The context suggests that this potential solution to Flem's problem is invented by Gavin as much if not more than by Flem.
For most of the Civil War Robert E. Lee commanded the Army of Northern Virginia. His surrender in April, 1865, to General Grant at Appomattox is commonly recognized as the point at which the War ended.