In the aftermath of his defeat at Gettysburg, Pennsylvania, Confederate General Robert E. Lee sends a letter of resignation as commander of the Army of Northern Virginia to Confederate President Jefferson Davis.

The letter came more than a month after Lee’s retreat from Pennsylvania. At first, many people in the South wondered if in fact Lee had lost the battle. Lee’s intent had been to drive the Union army from Virginia, which he did. The Army of the Potomac suffered over 23,000 casualties, and the Union army’s offensive capabilities were temporarily disabled. But the Army of Northern Virginia absorbed 28,000 casualties, nearly one-third of its total. As the weeks rolled by and the Union army reentered Virginia, it became clear that the Confederacy had suffered a serious defeat at Gettysburg. As the press began to openly speculate about Lee’s leadership, the great general reflected on the campaign at his headquarters in Orange Courthouse, Virginia.

The modest Lee took the failure at Gettysburg very personally. In his letter to Davis, he wrote, “I have been prompted by these reflections more than once since my return from Pennsylvania to propose to Your Excellency the propriety of selecting another commander for this army… No one is more aware than myself of my inability for the duties of my position. I cannot even accomplish what I myself desire… I, therefore, in all sincerity, request your Excellency to take measure to supply my place.”

Lee not only seriously questioned his ability to lead his army, he was also experiencing significant physical fatigue. He might also have sensed that Gettysburg was his last chance to win the war. Regardless, President Davis refused the request. He wrote, “To ask me to substitute you by someone… more fit to command, or who would possess more of the confidence of the army… is to demand an impossibility.”

READ MORE: Why the Civil War Actually Ended 16 Months After Lee Surrendered