Lee had slaves, but he thought that all slaves should have to work five years, but he also thought that ultimately, all slaves should be free. Lee also realized that having slaves in the South wasn't the most productive or economical choice for labor.
Robert E Lee was offered command of the Federal forces by Abraham Lincoln in 1861. Yet, Lee declined, and later that year, Virginia seceded from the Union. Lee joined Virginia, and was given command of the Virginian Army. He accepted, and he soon started attacking the good country that he once fought for against Mexico.