A plague is a busy time for a man of the cloth.

Cotton Mather was the most prominent clergyman in colonial Boston, the last in a line of preachers who had provided spiritual solace to the city from the beginning. Yet when he looked down from his pulpit in the fall of 1702 he saw his congregation dwindling by the day.

With funerals “daily celebrated and multiplied,” as he noted in his journal, the usual Puritan terrors of devils and Indians were replaced in public consciousness with fears of the “fevers and fluxes” that spread by the sad magic of human touch and breath.

Though best known for lighting the fuse of the Salem Witch Trials, Mather faced his greatest challenge not in the imagined spiritual malady of a few girls claiming to be hexed, but in the very real epidemic of small pox. His efforts to fight it, and his willingness to skirt theological orthodoxy in doing so, might stand today as a model for religious leaders to speak out against an anti-vaccine movement that represents a dangerous intersection of medical ignorance and misplaced spiritual confidence that Mather knew well.

By the reckoning of historians of the day, small pox made an appearance in Boston roughly every twenty years, always with disastrous effect.

“In one Twelve­month,” Mather wrote, “about one Thousand of our Neighbours have one way or other been carried unto their long Home.” In a population that had reached little more than 7,000 by then, the loss of 1,000 in a year made the epidemic seem like a surgeon’s handsaw cutting a body’s legs off at the shins.

This was not just a health crisis; it was also a theological one. The majority of Puritan clergy regarded the epidemic as divine will. To men like Mather, the cause of any catastrophe was clear enough. Years before, when he heard of an earthquake that destroyed the city of Port Royal in Jamaica, he believed the ground had shaken because the people of that colony had fallen into the heathen excitement of visiting fortunetellers. He likewise saw a direct connection between the number of miscarriages in Boston and the “great and visible decay of piety” in the city.  

The only explanation for suffering was the wrath of God, and so the only recourse they had was to determine which set of sins had unleashed it, and to find a way to atone.


Yet when the sickness hit close to home, Mather began to rethink this position. With his children suddenly showing symptoms he had seen so often when visiting the dying in “venomous, contagious, loathsome Chambers,” he began to wonder: If it was in man’s power to counteract illness through the God-­given gift of the intellect, would it not be wrong to squander grace by failing to do so?

Such thoughts lingered and faded through the years. And faded they might have remained were it not for a twist of fate that revealed something of the early influence of religious differences during the colonial era, and created America’s first bitter public health debate.

“This Day, a surprising Thing befel me,” Mather wrote in December 1706. “Some Gentlemen of our Church...purchased for me a very likely Slave.” This dubious perk from his congregation had come to Mather “without any Application of mine to them for such a Thing,” but he had certainly been in the market. It was well known, he wrote, “that I wanted a good Servant at the expence of between forty and fifty Pounds.”

Whether or not the man he renamed Onesimus became a Christian remains unknown. Mather was a proponent of the conversion of the enslaved, so it is likely an effort was made, but no mention of his baptism occurs in Mather’s diary. He does mention the conversion of later African­-born servants, so it seems likely that Onesimus held fast to whatever beliefs he had brought with him to Boston.

Once installed in the Mather home, Onesimus mainly performed daily tasks and lived in a room within the house. He thus had a front­-row seat when tragedy visited the minister’s life in the form of a measles outbreak that took three members of his family.

It was likely in the aftermath of this loss that Mather spoke with Onesimus about the servant’s experience with illness. Any student of New England history could have done the math and guessed that small pox might soon return to Boston, and so Mather asked the African-­born man if he had ever had the disease.

“Yes and no,” Onesimus cryptically replied.

To the momentarily confused Mather, Onesimus went on to explain that there was a practice in the place of his birth by which healthy young people were exposed to fluids from the bodies of the ill in order to protect them. So treated, they became sick for a time themselves, but with a far lower rate of full­-blown affliction. Whether he used the word or not, what he was describing was an early form of inoculation.

When Onesimus displayed on his arm a flash of scarred skin where the operation had been performed, it was as a revelation.  

Onesimus’s report so excited Mather that he sought out further accounts of the novel procedure. Though it was unheard of in practice among the physicians of New England, he discovered it was not entirely unknown elsewhere in Christendom and was, in fact, widely practiced throughout what Puritans knew as the heathen world. From Turkey to West Africa to the Levant, accounts of inoculation’s success reached European medical journals, where Mather himself later read of them. After studying reports printed in London about the practice, he wrote to the publisher and claimed a small portion of the glory of this discovery for himself.

“Many months before I mett with any Intimations of treating ye Small­Pox with the method of inoculation any where in Europe,” he wrote, “I had from a servant of my own an account of its being practised in Africa. Enquiring of my Negro man, Onesimus, who is a pretty Intelligent Fellow, Whether he had ever had the Small­Pox, he answered, both Yes and No; and then told me that he had undergone an Operation, which had given him something of ye Small­Pox and would forever preserve him from it; adding that it was often used among ye Guramantese and whoever had ye Courage to use it was forever free of the fear of contagion. He described ye Operation to me, and shew’d me in his Arm ye Scar which it had left upon him.”

From his letter we learn a number of things—some intended, some not. Mather regarded Onesimus as intelligent, and trusted his account of the events of his youth enough to relay it to medical professionals whom he wished to impress with his own comprehension of this surgical innovation. We also learn something about Mather’s opinion of himself as not merely a preacher from the hinterlands but an intellect worthy of being heard by the better minds of London. More importantly, we learn where in Africa Onesimus came into contact with this practice. By “Guramantese,” it is possible Mather was using an archaic name to refer to the Sahara tribe occupying present-­day Libya and Sudan. Given the trends in the enslaved population at the time, however, it is more likely Onesimus was a member of the Coramantee, residents of the Gold Coast. In later ethnographic accounts the region, it has been shown that the kind of inoculation Onesimus described often occurred within the context of religious rites.

Mather, scourge of witches, had become enamored with a practice his fellow Puritans would undoubtedly consider a heathen custom.


It is no surprise that he did not immediately shout from the rooftops of Boston his opinions concerning inoculation. It was one thing to write a letter to a medical society in London, quite another to announce to his fellow ministers that he had been taking lessons in the healing arts from an unbaptized African. It would take another five years, and another outbreak of the disease, before Mather would share what he had learned.

By 1721, Mather had seen three epidemics in his lifetime and had watched the losses mount every time. Of his fifteen children, nine died before adulthood. After a long career, Mather felt he had little to lose and much to gain by advocating a practice he knew could only scandalize his countrymen.

When he announced that he would deliver a plan to local physicians and ministers concerning what might be done about the return of the disease, his colleagues likely believed they knew what to expect.

They did not like what they heard. The report Mather prepared unambiguously supported inoculation, even as it traced the practice to areas firmly outside Christian influence. Not only did the assembled ministers scoff at the notion of following such ignoble precedents, the doctors were no more interested. As far as Mather could tell, only one of the local physicians gave the least bit of respect to his suggestion. “The Rest of the Practitioners,” he wrote, “treated the Proposal with an Incivility and an Inhumanity not well to be accounted for.”

The lone medical man in Boston intrigued by what he heard was Zabdiel Boylston, a surgeon who had achieved some renown a decade before when he removed a stone from the bladder of a young boy. As the first doctor in Boston to undertake internal surgery on a regular basis, he was a good man for Mather to have in his corner, even if his record of success made him a touch reckless in his approach.

So taken was Boylston by Mather’s presentation on inoculation that he went to work right away, experimenting first with members of his household: two servants and his own son. When news of this spread, the doctor came under attack. Against his new collaborator, Mather noted, “the vilest Arts were used, and with such an Efficacy, that not only the Physician, but also the Patients under the Small­Pox inoculated were in Hazard of their very Lives from an infuriated People.”

When surrounding towns declared the practice illegal and immoral, Mather and Boylston set about interviewing the slaves of Boston and found that most of them had received inoculation.

“I have since mett with a considerable Number of these Africans,” Mather later wrote, “who all agree in One story, That in their Country grandy­many dye of the Small­Pox.” Trying to capture the voices of those he interviewed, he continued in what he apparently considered a folksy dialect. “But now they learn This Way: People take Juice of Small­Pox; and Cutty­skin, and Putt in a Drop; then by’nd by a little Sicky, sicky: then very few little things like Small­Pox: and no body dy of it; and no body have Small­Pox any more.”

Armed with this evidence, Mather and Bolyston prepared a tract reporting their findings. In it, they issued a challenge to this last gasp of Puritan society to recognize the benefits that could be derived from paying attention to the varied knowledge cultural difference can provide. “I don’t know why ’tis more unlawful to learn of Africans, how to help against the Poison of the Small Pox,” they wrote, “than it is to learn of our Indians, how to help against the Poison of a Rattle­Snake.”


Counterarguments did nothing to silence his critics, however. Inoculation called into question the basic assumptions of the society the Puritans had built, and Mather’s support of it brought a violent reaction.

To treat small pox was seen as a form of blasphemy—a moral evil that refused to recognize that epidemics were acts of God. As one newspaper account of the controversy asked Mather pointedly, “Are you willing to imitate the Heathen in other Things besides Inoculation?”

In November of that plague­-ridden year, an opponent of Mather’s views threw a bomb with a lit fuse through his window. Had it gone off, Mather notes, it would “have killed them that were near it, and would have certainly fired the Chamber and speedily have laid the House in Ashes.”

Fortunately, the “grenado,” as he calls it, seems to have hit a metal casement as it came through the glass, dislodging the lit fuse, which burned out on the floor. This assault is said to have included a written message—“Cotton Mather, you dog, dam you! I’l inoculate you with this; with a pox to you”—but truly one might question the reliability of a story in which anyone finds it useful to attach a note to a bomb.

Nevertheless, the possibility of attack was a risk Mather was willing to take. Despite his long insistence on doctrinal purity, he had found a better way outside the bounds of his own tradition, and he was prepared to stake his reputation on arguing for the truth of it.

The anti-vaccine movement today is not solely religious in character, but much of its rhetoric is identical to theological arguments made against inoculation more than three hundred years ago. As the Florida-based organization KNOW (“Kids Need Options Without Vaccines”), puts it, “All vaccines are made in violation of God’s Word.” Such thinking is partly responsible for the worst measles epidemic in twenty years.

Mather himself lost children to measles; it’s clear which side of the vaccine debate one of the most important Christians in American history would be on.