Isaac Newton · every age

What was Isaac Newton doing at 28?

Invented calculus and gravity theory in a plague year at 23

1. c. 1671

   Wrote the Method of Fluxions at 28

   The calculus text stayed unpublished for decades. The Royal Society asked to see his telescope the same year.

   Source: en.wikipedia.org

Portrait: Portrait: Godfrey Kneller (1689), public domain, via Wikimedia Commons · source