**Today’s Google Doodle honors a Swiss mathematician named Leonhard Euler. The 18th-century numbers whiz is credited with being the most prolific mathematician in history, according to a biography posted online at the University of St. Andrews, Scotland.**

“Euler has to be considered as one of the dozen or so most influential mathematicians of all time, alongside Archimedes, Euclid, al-Khwarizmi, and Newton,” wrote Keith Devlin, a mathematician at Stanford University in California, in an email.

Euler was the first to use Venn diagrams to show the relationships between sets, or collections, of numbers. He extended Sir Isaac Newton’s second law of motion, which explains how an object’s speed and direction changes when a force is applied (otherwise known as *f=ma*), and authored 886 papers and books despite going blind in his mid-50s. He touched so many branches of mathematics—including geometry, trigonometry, and calculus—and physics that terms like “Euler’s formula” of “Euler’s equation” can mean different things depending on the specific field.

Born in Basel, Switzerland in 1707, the young Euler got into the University of Basel at 13 and received a master’s degree by 16. He trained with renowned Swiss mathematician Johann Bernoulli, published his first scientific paper by 19—which won him a prize from the Paris Academy of Sciences—and then spent most of his academic life in St. Petersburg, Russia, and Berlin.

Euler was so prolific that even after he died in 1783, the St. Petersburg Academy kept publishing his works for at least 30 years after his death. He was married twice and had 13 children, although all but five of them died young.