Isaac Newton · every age

What was Isaac Newton doing at 26?

Invented calculus and gravity theory in a plague year at 23

1. c. 1669

   Lucasian Professor of Mathematics at 26

   His teacher Isaac Barrow stepped down in his favour.

   Source: en.wikipedia.org

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