Fact 1261 — Newton and the plague years

When plague interrupted study at Cambridge, Isaac Newton returned to Woolsthorpe and spent about 18 months there in 1665–1666. He later remembered those years as an especially productive period for mathematics and natural philosophy; optics and an early form of calculus were among the subjects of his work around this time. However, his scientific work began earlier and continued afterward, and different works appeared in different years: the *Principia* was published in 1687. So not all of his discoveries were made during those 18 months, and they did not all share the same publication delay. The illustration is AI-generated.