Leonhard Euler was born on April 15, 1707 in Basel Switzerland, the son of a Protestant minister. He entered the University of Basel in 1720 to study theology and follow his father's path. However, he switched to the study of mathematics after his talents were discovered by Johan Bernoulli. In 1726 Euler accepted an academic post at the University of St. Petersburg in Russia. He moved to Berlin in 1741 to become director of mathematics at the newly formed Berlin Academy of Sciences. After 25 years in Berlin, Euler returned to St. Petersburg in 1766. An illness left him blind in 1771, but did not diminish his mathematical output. Euler died in St. Petersburg on September 18, 1783.
Leonhard Euler is one of the most important figures in the history of mathematics. He made fundamental contributions in number theory, calculus, differential equations, geometry, the calculus of variations, and complex analysis. His applied work includes problems in astronomy, fluid mechanics, elasticity, optics, ballistics, cartography, ship building, and music. A prolific and tireless author, Euler wrote hundreds of papers. He is responsible for many mathematical notations that are now standard.