A portrait of George Armstrong Custer around 1900.
One of the most celebrated Union cavalry commanders in the Civil War, George Armstrong Custer famously pursued Robert E. Lee and was present at his 1865 surrender at Appomattox. After the war, however, Custer decided he needed a break—and took one without leave. Despite orders to join Gen. Winfield S. Hancock in Kansas for a campaign against the Cheyenne, Custer left his post to visit his wife. For being AWOL, Custer was court-martialed in 1867, sent to Fort Leavenworth, and suspended for a year without pay. Within months, he was reinstated amid hostility with the Plains Indians. He might have been better off in prison—nine years later, he died fighting the Lakota and Cheyenne at the Battle of Little Big Horn.