Introducing a small amount of smallpox virus by inhaling through the nose or by making a number of small pricks through the layers of skin (variolation) to create resistance to the disease began in the 10th or 11th century in Central Asia. Variolation was introduced into England in 1721. There, in 1798, Edward Jenner began treatments against smallpox, the first systematic effort to control a disease through immunization.