"Secret or not, the practice of inoculation traveled west toward the Ottoman Empire in the 1500s, reaching Constantinople (modern day Istanbul, Turkey) in the mid-1600s. From there, inoculation traveled to Europe and Northern Africa. From Northern Africa, the practice traveled to the Massachusetts Colony through an enslaved man named Onesimus. He told Reverend Cotton Mather -- of Salem Witchcraft Trials fame -- about being inoculated by enslavers to resist smallpox and get better pay for his enslavement. Cotton Mather, together with a local doctor in Boston, adopted and promoted inoculation as a deadly smallpox epidemic arrived in Boston in 1721. Around the same time, Lady Mary Wortley Montague, a British socialite living in Constantinople with her diplomat husband, had her son inoculated by a local physician. She then asked her daughter -- back home in Scotland -- to be inoculated. By 1723, the evidence was clear that inoculation in a controlled setting and under the supervision of a physician was preferable to catching smallpox "the natural way." After his son died from smallpox in 1736, Benjamin Franklin became a champion of inoculation. He wrote several introductions to written works of the time about the procedure. In one such document written in 1759, Benjamin Franklin even included some numbers on the death rates of those who were inoculated (also known as "variolated"). The numbers gave even more proof that the risk of death was lower in those who were inoculated, cementing the practice in Europe and North America. Such was the adoption of variolation that General George Washington ordered the American troops to be inoculated as part of their intake into the Continental Army during the American Revolutionary War."