Leonhard Euler, (born April 15, 1707, died Sept. 18, 1783), was the most prolific mathematician in history. His 866 books and articles represent about one third of the entire body of research on mathematics, theoretical physics, and engineering mechanics published between 1726 and 1800. In pure mathematics, he integrated Leibniz's differential calculus and Newton's method of fluxions into mathematical analysis; refined the notion of a function; made common many mathematical notations, including e, i, the pi symbol, and the sigma symbol; and …showed first 75 words of 542 total…

…showed last 75 words of 542 total…matters. Frederick was greatly angered at his departure and invited Lagrange to replace him. In Russia, Euler became almost entirely blind after a cataract operation, but was able to continue with his research and writing. He had a phenomenal memory and was able to dictate treatises on optics, algebra, and lunar motion. At his death in 1783, he left a vast backlog of articles. The St. Petersburg Academy continued to publish them for nearly 50 more years.