The banknote of 10 Swiss francs once featured the portrait of Leonhard Euler. His image could have been depicted on Russian ruble banknotes too, as the famous scientist lived and worked in Russia for a half of his life.

In 1727, native of Basel, son of a pastor and favorite student of outstanding mathematician Johann Bernoulli, Leonhard Euler came to Saint Petersburg on the invitation of Catherine I. The widow of Peter the Great failed to live to his arrival, yet young Euler settled down successfully in unknown Russia and started helping to create Russian science from the scratch. He worked a lot: specialists call Euler the most prolific scientist of the 18^th century. The list of his scholar papers includes more than 800 works. During the rule of infant Ioann Antonovich, Saint Petersburg Academy of Sciences fell to desolation, and Euler left for Berlin on personal invitation of Friedrich the Great. However, the scientist came back to Russia in 1766 responding to the call of Catherine the Great. The Russian empress allocated much more money to science if compared to stingy Friedrich II, and this fact did the trick. The scholar papers in mathematical analysis, differential geometry, theory of numbers, approximate computing, and celestial mechanics made Leonhard Euler the most outstanding mathematician of his century. Since that time, a sufficient part of mathematics has been taught according to Euler. Even school children know the base of natural logarithms – E. This invariable was named in honor of Leonhard Euler. “He stopped living and computing,” this is how Euler’s death was announced in the Paris Academy of Sciences. The grave of the outstanding mathematician is in Saint Petersburg. The epitaph says: “Here lie the mortal remains of wise, just, and famous Leonhard Euler.”