Onesimus Introduces Smallpox Inoculation to America

Onesimus, an enslaved African man owned by Puritan minister Cotton Mather in Boston, described the African practice of variolation (deliberate inoculation with smallpox matter) to Mather during the 1721 smallpox epidemic. Mather promoted the technique, and Dr. Zabdiel Boylston applied it — saving hundreds of lives in what became the first major deployment of inoculation in American history. Onesimus's knowledge, drawn from African medical traditions, is credited by historians as the direct source of this life-saving intervention and an early example of African knowledge shaping American medicine.