Robert E. Lee's "greatness" did not come from being a General in the Confederate Army.
He "greatness" can be attributed to his unwavering devotion to his God and his family, his sense of loyalty to his ancestral State of Virginia, and his compassion & concern for the men who so bravely fought by his side throughout the war.
He was, first and foremost, a gentleman of excellant character, an honorable man, respected by his peers, as well as those who opposed him, including U. S. Grant and President Lincoln.
Robert E. Lee's decision to join the Confederacy, was made with a heavy heart, knowing that the loss of life for thousands of good men would be his responsibility.
Lee, above all other's, understood the meaning of the word "patriotism". His father was Lighthorse Harry Lee, who had served with General Washington, during the Revolutionary War. His uncles, Richard Henry Lee and Frances Lightfoot Lee, were the only two brothers to sign the Declaration of Independence. Richard Henry Lee was a member of the House of Burgesses in Virgina and one of the premier orators of the fight for America's freedom from the tyranny of England and he was second only to Patrick Henry.
When Lee rode his faithful steed, Traveler, along the dusty road leading to the McClean house, where he was to surrender to Grant, it was lined with men from both sides. As he passed, both Union and Confederate soldiers were so impressed by his presences, they removed their caps, stood at attention and saluted, out of respect.
Lee's "greatness" can not be measured by "what" he was; it must be measured by "who" he was.