Final answer:
Robert E. Lee was the commander of the Army of Northern Virginia, whose significant command included engaging in key battles against Union forces and eventually surrendering to Ulysses S. Grant, marking a decisive end to the Civil War.
Step-by-step explanation:
The commander of the Army of Northern Virginia was Robert E. Lee, a prominent Confederate general during the American Civil War. This army was one of the primary military forces of the Confederate States of America, fighting mainly in the Eastern Theater of the Civil War.
The significance of Lee's command includes his tactical expertise and the strategic importance of his battles against Union forces. Notably, under Lee's command, the Army of Northern Virginia was involved in crucial battles such as the Seven Days Battles, where he fought against Union General George B. McClellan. Despite some successes, it was Lee's surrender to Union General Ulysses S. Grant at Appomattox Court House that marked a decisive end to the Civil War. Lee's command, strategies, and eventual surrender significantly impacted the outcome of the war, shaping the course of American history.