Robert E. Lee, Joining the Confederacy (American National Biography)

On 18 April [1861], following the bombardment of Fort Sumter on 12-14 April, Francis Preston Blair, Sr., on behalf of President Abraham Lincoln, directly asked Lee whether he would take command of an enlarged U.S. Army. But Lee reiterated what he had said to [General Winfield] Scott. On 20 April, having learned that Virginia had seceded two days earlier, Lee submitted his resignation. It was a painful decision but one that in its expression of loyalty to home and kindred has commanded sympathy even from those who cannot admire it.

On 21 April Governor John Letcher of Virginia dispatched a messenger offering Lee command of the military and naval forces of the state, with the rank of major general, but the messenger evidently passed Lee while the latter was en route from Arlington to Richmond in response to an earlier invitation from the governor. Lee accepted the commission from Letcher's hand on 22 April. On 10 May the Confederate War Department gave Lee command of its forces in Virginia, though it proceeded to send troops and other officers there apparently without regard to him. Following the voters' ratification of the Virginia Ordinance of Secession on 23 May, the state turned over its forces to the Confederacy on 8 June, while Lee had already been commissioned brigadier general in the Confederate regular army on 14 May.