Sonia Kovalevsky was the most widely known Russian mathematician of the late 19th century. She was born Sonia Korvin to a family of the minor nobility in Moscow in 1850. (Her father was an artillery general.) She developed an early interest in poetry and mathematics. When her father objected to her studies, she continued them secretly. She did not receive a formal mathematics education in Russia. She was exposed to mathematics in a curious way. During the renovation of the family country estate, one of the children's rooms was temporarily wallpapered with some notes from a text on calculus. In her autobiography, A Russian Childhood, she recalled that she had "passed hours before that mysterious wall, trying to decipher even a single phrase and to discover the order in which the sheets ought to follow each other." At age 15 in St. Petersburg she took private lessons from a professor at the naval academy who was astounded with the quickness with which she grasped ideas. One of the few ways for a Russian woman to continue her education was to study at a foreign university. In 1868 she married Vladimir Kovalevsky and they moved to Germany the next year where they both continued their studies at Heidelberg University. At that time, German universities admitted no women students except those from abroad. Even after this barrier fell, women in Prussia did not have the right to qualify for higher degrees. Sonia obtained special permission to attend several courses. The teachings of Leo Konigsberger, who had been one of the first pupils of the great Karl Weierstrass, had the greatest effect on her. At the end of 1870, she transferred to Berlin to learn from the master himself. Weierstrass was soon impressed by her ability and claimed that she had "the gift of intuitive genius" to a degree he seldom found among his advanced students. The University of Berlin was more conservative than Heidelberg and Sonia was not allowed to take courses. When all of Weierstrass' attempts to get this ban lifted for her failed, he offered to work with her privately. By 1874 Sonia had completed three outstanding research papers. The strength of these works, along with Weierstrass' strong recommendation, qualified her for a doctorate without examination and in absentia, from the University of Gottingen (which she never actually attended). This was the first time that a woman had applied for a higher degree in mathematics, so Weierstrass requested that the university be particularly careful to uphold high standards in judging her. The first Ph.D. earned by a woman in mathematics was awarded to Sonia Kovalevsky summa cum laude (with highest honors). Despite her advanced degree and strong letters of recommendation, she was unable to obtain an academic position anywhere in Europe. She returned to St. Petersburg where during her absence, the advocates of higher education for women had managed to institute a program known as Higher Courses for Women in several universities. However Russian law prevented a woman from holding a position at a university. For nine years she occupied herself with various nonscientific pursuits: she wrote newspaper articles, theater reviews, poetry and a short novel. Although Weierstrass' letters kept her in touch with recent mathematical advances, she was on the verge of abandoning mathematics. Finally in 1883, Sonia was invited by Gosta Mittag-Leffler, another of Weierstrass's distinguished students, to teach at the newly formed University of Stockholm. Sonia's prominence as a professional mathematician reached its apex in 1888 when she received the prestigious Prix Bordin from the French Academie des Sciences for one of her research papers. Voting unanimously in favor of the winning paper, the selection committee, unaware that the writer was a woman (the papers were submitted anonymously), "recognized in this work not only the power of an expansive and profound mind, but also a great spirit of invention." Due to the exceptional merit of the work, the prize was raised from 3,000 to 5,000 francs, a considerable sum of money at that time. In 1889 Sonia was appointed a full professor of mathematics at Stockholm, she held this office until her untimely death due to influenza less than two years later. Adapted from History of Mathematics by David M. Burton.