One day in January, a few years before the Civil War, Robert E. Lee wrote to The New York Times, seeking a correction.

The man who would become the top Confederate general was trying to set the record straight about the slaves on his wife’s estate in Virginia, and about the last wishes of a dying slave owner.

He wrote that the people enslaved on his family’s property, in what was then known as Alexandria County, were not “being sold South,” as had been reported. And he implied that he would free them within five years.

The letter is one of many written by Lee that sheds slivers of light on his thoughts about slavery. Historians have clashed — and are clashing still — over the strength of his support for the system of forced labor that kept millions of people in bondage for generations.