This is part of what Wikipedia says about Thomas Jefferson and slaves:


    "Jefferson was an outspoken abolitionist, but he owned many slaves over his lifetime. Although these facts seem baffling, biographers point out that Jefferson was deeply in debt and had encumbered his slaves by notes and mortgages; he could not free them until he was free of debt, which never happened...

    "The downturn in land prices after 1819 pushed Jefferson further into debt. Jefferson finally emancipated his five most trusted slaves (two, his alleged mixed-race sons) and petitioned the legislature to allow them to stay in Virginia. After his death, his family sold the remainder of the slaves by auction on the lawn of his estate[94] to settle his high debts."