I have read Free in Chains as well. It is an excellent book to understand the very complex laws involving Free People of Color and Indians in the Colonial South. Rachel's 'owner' simply changed her race on a bill of sale stating she was a 'negro slave.' In fact when she went into court many years later the judge actually asked her if she was sure it was not her father who was indian. Meaning if her father had been indian and not her mother, she would still be a slave. Indians in the upper south came into court many times to assert their right to freedom based on descent from an Indian woman.