Which century was Isaac Newton born in?

Isaac Newton was born in the 1600s, specifically in 1642 by England’s calendar at the time. That places him in the 17th century, which runs from 1601 through 1700.

Newton was born at Woolsthorpe Manor in Lincolnshire, England. His birth date is commonly recorded as 25 December 1642 under the Julian calendar, then used in England; converted to the modern Gregorian calendar, it was 4 January 1643. Both dates refer to the same birth.

Newton later became one of history’s most influential mathematicians and physicists. His 1687 book Philosophiæ Naturalis Principia Mathematica described the laws of motion and universal gravitation, helping establish classical mechanics. A common mix-up is to call Newton an 18th-century scientist because he lived until 1727 and did important work after 1700, but his birth clearly belongs to the 1600s.