Leonhard Euler (/ˈɔɪlər/ OY-lər; German: [ˈɔʏlɐ] (About this soundlisten); 15 April 1707 – 18 September 1783) was a Swiss mathematician, physicist, astronomer, geographer, logician and engineer who made important and influential discoveries in many branches of mathematics, such as infinitesimal calculus and graph theory, while also making pioneering contributions to several branches such as topology and analytic number theory. He also introduced much of the modern mathematical terminology and notation, particularly for mathematical analysis, such as the notion of a mathematical function. He is also known for his work in mechanics, fluid dynamics, optics, astronomy and music theory.
Euler was one of the most eminent mathematicians of the 18th century and is held to be one of the greatest in history. He is also widely considered to be the most prolific, as his collected works fill 92 volumes, more than anyone else in the field. He spent most of his adult life in Saint Petersburg, Russia, and in Berlin, then the capital of Prussia.
A statement attributed to Pierre-Simon Laplace expresses Euler’s influence on mathematics: “Read Euler, read Euler, he is the master of us all.”
Leonhard Euler was born on 15 April 1707, in Basel, Switzerland, to Paul III Euler, a pastor of the Reformed Church, and Marguerite née Brucker, another pastor’s daughter. He had two younger sisters, Anna Maria and Maria Magdalena, and a younger brother, Johann Heinrich. Soon after the birth of Leonhard, the Eulers moved from Basel to the town of Riehen, Switzerland, where Leonhard spent most of his childhood. Paul was a friend of the Bernoulli family; Johann Bernoulli, then regarded as Europe’s foremost mathematician, would eventually be the most important influence on young Leonhard.
Euler’s formal education started in Basel, where he was sent to live with his maternal grandmother. In 1720, at age thirteen, he enrolled at the University of Basel. In 1723, he received a Master of Philosophy with a dissertation that compared the philosophies of Descartes and Newton. During that time, he was receiving Saturday afternoon lessons from Johann Bernoulli, who quickly discovered his new pupil’s incredible talent for mathematics. At that time Euler’s main studies included theology, Greek and Hebrew at his father’s urging to become a pastor, but Bernoulli convinced his father that Leonhard was destined to become a great mathematician.
In 1726, Euler completed a dissertation on the propagation of sound with the title De Sono. At that time, he was unsuccessfully attempting to obtain a position at the University of Basel. In 1727, he first entered the Paris Academy Prize Problem competition; the problem that year was to find the best way to place the masts on a ship. Pierre Bouguer, who became known as “the father of naval architecture”, won and Euler took second place. Euler later won this annual prize twelve times.