Onesimus (fl. 1706 – 1717), slave and medical pioneer, was born in the late seventeenth century, probably in Africa, although the precise date and place of his birth are unknown. He first appears in the historical record in the diary of Cotton Mather, a prominent New England theologian and minister of Boston’s Old North Church. Reverend Mather notes in a diary entry for 13 December 1706 that members of his congregation purchased for him “a very likely Slave; a young Man who is a Negro of a promising aspect of temper” (Mather, vol. 1, 579). Mather named him Onesimus, after a biblical slave who escaped from his master, an early Christian named Philemon.
This Onesimus fled from his home in Colossae (in present-day Turkey) to the apostle Paul, who was imprisoned in nearby Ephesus. Paul converted Onesimus to Christianity and sent him back to Philemon with a letter, which appears in the New Testament as Paul’s Epistle to Philemon. In that letter Paul asks Philemon to accept Onesimus “not now as a servant, but above a servant, a brother beloved” (Philemon 1.16 [AV]). Mather similarly hoped to make his new slave “a Servant of Christ,” and in a tract, The Negro Christianized (1706), encouraged other slave-owners to do likewise, believing that Christianity “wonderfully Dulcifies, and Mollifies, and moderates the Circumstances” of bondage (Silverman, 264).
Onesimus was one of about a thousand persons of African descent living in the Massachusetts colony in the early 1700s, one-third of them in Boston. Many were indentured servants with rights comparable to those of white servants, though an increasing number of blacks–and blacks only–were classified as chattel and bound as slaves for life. Moreover, after 1700, white fears of burglary and insurrection by blacks and Indians prompted the Massachusetts assembly to impose tighter restrictions on the movements of people of color, whether slave, servant, or free. Cotton Mather was similarly concerned in 1711 about keeping a “strict Eye” on Onesimus, “especially with regard unto his Company,” and he also hoped that his slave would repent for “some Actions of a thievish aspect” (Mather, vol. 2, 139). Mather believed, moreover, that he could improve Onesimus’s behavior by employing the “Principles of Reason, agreeably offered unto him” and by teaching him to read, write, and learn the Christian catechism. (Mather, vol. 2, 222).
What Onesimus thought of Mather’s opinions the historical record does not say, nor do we know much about his family life other than that he was married and had a son, Onesimulus, who died in 1714. Two years later Onesimus gave the clearest indication of his attitude toward his bondage by attempting to purchase his release from Mather. To do so, he gave his master money toward the purchase of another black youth, Obadiah, to serve in his place. Mather probably welcomed the suggestion, since he reports in his diary for 31 August 1716 that Onesimus “proves wicked, and grows useless, Froward [ungovernable] and Immorigerous [rebellious].” Around that time Mather signed a document releasing Onesimus from his service “that he may Enjoy and Employ his whole Time for his own purposes and as he pleases” (Mather, vol. 2, 363). However, the document makes clear that Onesimus’s freedom was conditional on performing chores for the Mather family when needed, including shoveling snow, piling firewood, fetching water, and carrying corn to the mill. This contingent freedom was also dependent upon his returning a sum of five pounds allegedly stolen from Mather.
Little is known of Onesimus after he purchased his freedom, but in 1721 Cotton Mather used information he had learned five years earlier from his former slave to combat a devastating smallpox epidemic that was then sweeping Boston. In a 1716 letter to the Royal Society of London, Mather proposed “ye Method of Inoculation” as the best means of curing smallpox and noted that he had learned of this process from “my Negro-Man Onesimus, who is a pretty Intelligent Fellow” (Winslow, 33). Onesimus explained that he had undergone an Operation, which had given him something of ye Small-Pox, and would forever preserve him from it, adding, That it was often used among [Africans] and whoever had ye Courage to use it, was forever free from ye Fear of the Contagion. He described ye Operation to me, and showed me in his Arm ye Scar.” (Winslow, 33)
Reports of similar practices in Turkey further persuaded Mather to mount a public inoculation campaign. Most white doctors rejected this process of deliberately infecting a person with smallpox–now called variolation–in part because of their misgivings about African medical knowledge. Public and medical opinion in Boston was strongly against both Mather and Dr. Zabdiel Boylston, the only doctor in town willing to perform inoculations; one opponent even threw a grenade into Mather’s home. A survey of the nearly six thousand people who contracted smallpox between 1721 and 1723 found, however, that Onesimus, Mather, and Boylston had been right. Only 2 percent of the six hundred Bostonians inoculated against smallpox died, while 14 percent of those who caught the disease but were not inoculated succumbed to the illness.
It is unclear when or how Onesimus died, but his legacy is unambiguous. His knowledge of variolation gives the lie to one justification for enslaving Africans, namely, white Europeans’ alleged superiority in medicine, science, and technology. This bias made the smallpox epidemic of 1721 more deadly than it need have been. Bostonians and other Americans nonetheless adopted the African practice of inoculation in future smallpox outbreaks, and variolation remained the most effective means of treating the disease until the development of vaccination by Edward Jenner in 1796.