He was a Romanian-Armenian mathematician, astronomer and politician. He made a fundamental contribution to the n-body problem in celestial mechanics by proving that using a third degree approximation for the disturbing forces implies instability of the major axes of the orbits, and by introducing the concept of secular perturbations in relation to this. <br /> As a politician, during his three terms as Minister of Education, SpiruHaret ran deep reforms, building the modern Romanian education system. He was made a full member of the Romanian Academy in 1892 and a crater on the Moon is named after him.<br /> He showed an early talent for mathematics, publishing two textbooks (one in algebra and one in trigonometry) when he was still a high school student.<br /> In this work he proved a result fundamental for the n-body problem in astronomy, the thesis being published in Vol. XVIII of the Annales de l'Observatoire de Paris. He was the first Romanian to obtain a Ph.D. degree in Paris.<br /> After his return to Romania in 1878, he abandoned scientific research and dedicated the rest of his life to improving Romanian education, which was heavily underdeveloped at the time, both as professor and as politician. He was appointed professor of rational mechanics at the Science Faculty in Bucharest. The next year (1879), he became a correspondent member of the Romanian Academy, receiving full membership in 1892. <br /> He’s major scientific contribution was made in 1878, in his Ph.D. thesis Surl’invariabilité des grandes axes des orbitesplanétaires. At the time it was known that planets disturbe each other’s orbits, thus deviating from the elliptic motion described by Johannes Kepler’s First Law. Henri Poincaré considered this result a greatsurprise and continued he’s research, which eventually led him to the creation of chaos theory. In 1910 he published Social mechanics, which used mathematics to explain social behavior<br />
He was a Moldavian-born Romanian politician who ruled as the first Domnitor of the United Principalities of Wallachia and Moldavia between 1859 and 1866. <br /> He received an urbane European education, becoming an officer in the Moldavian Army (rising to the rank of colonel). He married Elena Rosetti in 1844.<br /> In 1848, known as the year of European revolutions, Moldavia and Wallachia fell into revolt. He became Moldavia's minister of war in 1858, and represented Galaţi in the ad hoc Divan at Iaşi, acting under the guarantee of the European Powers in the wake of the Crimean War to nominate a prince for Moldavia.In default of a foreign prince, he was himself nominated in both countries by the pro-unionist PartidaNaţională and elected prince of Moldavia on 17 January 1859 and, after street pressure changed the vote in Bucharest, of Wallachia on 5 February 1859. <br />He initiated a series of reforms that contributed to the modernization of Romanian society and of state structures:<br /><ul><li>His first measure addressed a need for increasing the land resources and revenues available to the state, by confiscating monastic assets.
The land reform, liberating peasants from the last corvées, freeing their movements and redistributing some land, was less successful.
He's reforms also included the adoption of the Criminal Code and the Civil Code based on the Napoleonic code
The Law of Education, establishing tuition-free, compulsory public education for primary schools.</li></ul>He founded the University of Iaşi and the University of Bucharest, and helped develop of a modern, European-style Romanian Army, under a working relationship with France.<br />
He was twice Prince of Moldavia (in March-April 1693 and in 1710–1711). He was also a prolific man of letters– philosopher, historian, composer, musicologist, linguist, ethnographer, and geographer. <br /> His education began at home, where he learned Greek and Latin and acquired a profound knowledge of the classics. In 1693, he succeeded his father as Prince of Moldavia, but he had ruled only for less than a year. <br /> In 1714 Cantemir became a member of the Royal Academy of Berlin. Between 1711 and 1719 he wrote his most important creations. Cantemir was known as one of the greatest linguists of his time, speaking and writing eleven languages, and being well versed in Oriental scholarship. His oeuvre is voluminous, diverse, and original; although some of his scientific writings contain unconfirmed theories and inaccuracies, his expertise, sagacity, and groundbreaking researches are widely acknowledged.<br /> The best known is his ’’ History of the Growth and Decay of the Ottoman Empire’’. This volume circulated throughout Europe in manuscript for a number of years. It was finally printed in 1734 in London, and later it was translated and printed in Germany and France. He wrote the first geographical, ethnographical and economic description of Moldavia, DescriptioMoldaviae.<br /> He wrote the first Romanian language novel, the cryptic HistoriaHieroglyphica (1705), to which he furnished a key, and in which the principal persons are represented by mythological beasts. His name is among those who were considered to be the brightest minds of the world on a plaque at the Library of Sainte-Genevieve in Paris, next to those of Leibnitz, Newton, Piron, and other great thinkers.<br />