An Enslaved Man’s Knowledge Brings Inoculation to Boston

In late 1706, members of the North Church congregation in Boston purchased an enslaved African man and presented him as a gift to their prominent Puritan minister, Cotton Mather. Mather renamed the man Onesimus after an enslaved figure mentioned in the New Testament whose name denoted utility. Historical records do not record Onesimus's original birth name or precise birthplace, though Mather described his background as Guaramantee, a term scholars associate with the Coromantee or Akan people of contemporary Ghana. While living and working under enslavement in Boston, Onesimus learned to read and write alongside the Mather family, earned independent wages, and maintained a separate household with his wife.

Around 1716, Onesimus provided Mather with a detailed description of an operation that had protected him from smallpox prior to his arrival in the Massachusetts Bay Colony. Variolation, a long-standing preventive measure among sub-Saharan African societies, involved taking fluid from an active smallpox pustule, cutting or puncturing the skin of a healthy person, and introducing a small amount of the infected material. Onesimus displayed his own scar and explained that this practice conferred lifelong resistance while producing far milder illness than a natural infection. Mather later confirmed the account by questioning other Africans in Boston, who described similar practices.