Mathematician. His father had some mathematical training and was able to teach his son elementary mathematics along with other subjects. Euler's father wanted his son to follow him into the church and sent him to the University of Basel to prepare for the ministry. He entered the University in 1720, at the age of 14, first to obtain a general education before going on to more advanced studies. In 1723 Euler completed his Master's degree in philosophy having compared and contrasted the philosophical ideas of Descartes and Newton. However, although he was to be a devout Christian all his life, he could not find the enthusiasm for the study of theology, Greek and Hebrew that he found in mathematics. He obtained his father's consent to change to mathematics. By 1726 he had already an article in print and was offered the post in Russian Academy of Sciences which would involve him in teaching applications of mathematics and mechanics to physiology. He also served as a medical lieutenant in the Russian navy from 1727 to 1730. In 1730 he became professor of physics at the Academy and, since this allowed him to become a full member of the Academy, he was able to give up his Russian navy post. The publication of many articles and his book Mechanica, which extensively presented Newtonian dynamics in the form of mathematical analysis for the first time, started him on the way to major mathematical work. By 1740 he had a very high reputation, having won the Grand Prize of the Paris Academy in 1738 and 1740. He was offered to go to Berlin, but at first he preferred to remain in St Petersburg. However political turmoil in Russia made the position of foreigners particularly difficult and contributed to Euler changing his mind. Accepting an improved offer from Frederick the Great, he went to Berlin, where he continued to receive part of his salary from Russia. For this remuneration he bought books and instruments for the St Petersburg Academy, continued to write scientific reports for them, and educated young Russians. During the twenty-five years spent in Berlin, he wrote around 380 articles, books on the calculus of variations; on the calculation of planetary orbits; on artillery and ballistics; on analysis; on shipbuilding and navigation; on the motion of the moon; lectures on the differential calculus. In 1759 he assumed the leadership of the Berlin Academy, although not the title of President because of some disagreements with the king. In 1766 Euler returned to St Petersburg and Frederick was greatly angered at his departure. Soon after his return to Russia, Euler became totally blind. Because of his remarkable memory he was able to continue with his work on optics, algebra, and lunar motion, producing almost half his total works. After his death the St Petersburg Academy continued to publish Euler's unpublished work for nearly 50 more years.