Onesimus (late 1600s–1700s) was an African man who was instrumental in the mitigation of the impact of a smallpox outbreak in Boston, Massachusetts. His birth name is unknown. He was enslaved and, in 1706, was given to the New England Puritan minister Cotton Mather, who renamed him. Onesimus introduced Mather to the principle and procedure of the variolation method of inoculation to prevent the disease, which laid the foundation for the development of vaccines. After a smallpox outbreak began in Boston in 1721, Mather used this knowledge to advocate for inoculation in the population. This practice eventually spread to other colonies. In a 2016 Boston magazine survey, Onesimus was declared one of the "Best Bostonians of All Time"
Onesimus's name at birth and place of birth are unknown with certainty. He was first documented as living in the colonies in 1706, having been brought to North America as an enslaved person. In December of that year, he was given as a gift by a church congregation to Cotton Mather, their Puritan minister of North Church, as well as a prominent figure in the Salem Witch Trials. Mather renamed him after a first-century AD enslaved person mentioned in the Bible.The name, "Onesimus" means "useful, helpful, or profitable".
Mather referred to the ethnicity of Onesimus as "Guaramantee", which may refer to the Coromantee (also known as Akan people of modern Ghana).Â
Mather saw Onesimus as highly intelligent and educated him in reading and writing with the Mather family (for context, according to biographer Kathryn Koo, at that time, literacy was primarily associated with religious instruction, and writing as means of note-taking and conducting business)
In 1716 or shortly before, Onesimus had described to Mather the process of inoculation that had been performed on him and others in his society in Africa (as Mather reported in a letter): "People take Juice of Small-Pox; and Cut the Skin, and put in a drop." In the book, African Medical Knowledge, the Plain Style, and Satire in the 1721 Boston Inoculation Controversy, Kelly Wisecup wrote that Onesimus is believed to have been inoculated at some point before being sold into slavery or during the slave trade, as he most likely traveled from the West Indies to Boston.
The variolation method of inoculation was long practiced in Africa among African people.
The practice was widespread among enslaved colonial people from many regions of Africa and, throughout the slave trade in the Americas, slave communities continued the practice of inoculation despite regional origin.
Mather followed Onesimus's medicinal advice because, as Margot Minardi writes, "inferiority had not yet been indelibly written onto the bodies of Africans."
