 franÃ§ois viÃ¨te (latin: franciscus vieta; 1540 â 23 february 1603), seigneur de la bigotiÃ¨re, was a french mathematician whose work on new algebra was an important step towards modern algebra, due to its innovative use of letters as parameters in equations. he was a lawyer by trade, and served as a privy councillor to both henry iii and henry iv. == biography == === origins === viete was born at fontenay-le-comte, vendÃ©e. his grandfather was a merchant from la rochelle. his father, etienne viÃ¨te, was an attorney in fontenay-le-comte and a notary in le busseau. his mother was the aunt of barnabÃ© brisson, a magistrate and the first president of parliament during the ascendancy of the catholic league of france. vieta went to a franciscan school and in 1558 studied law at poitiers, graduating as a bachelor of law in 1559. a year later, he began his career as an attorney in his native town. from the outset, he was entrusted with some major cases, including the settlement of rent in poitou for the widow of king francis i of france and looking after the interests of mary, queen of scots. === serving parthenay === in 1564, vieta entered the service of antoinette dâaubeterre, lady soubise, wife of jean v de parthenay-soubise, one of the main huguenot military leaders and accompanied him to lyon to collect documents about his heroic defence of that city against the troops of jacques of savoy, 2nd duke of nemours just the year before. the same year, at parc-soubise, in the commune of mouchamps, vendÃ©e, vieta became the tutor of catherine de parthenay, soubise's twelve-year-old daughter. he taught her science and mathematics and wrote for her numerous treatise on astronomy, geography and trigonometry, some of which have survived. in these treatise, vieta used decimal numbers (twenty years before stevin's paper) and he also noted the elliptic orbit of the planets,{{citation|title=the cosmos of science: essays of exploration|series=pittsburgh-konstanz series in the philosophy and history of science|editor1-firs
1540_births 1603_deaths 16th-century_French_mathematicians Algebraists French_cryptographers People_from_Fontenay-le-Comte Pre-19th-century_cryptographers University_of_Poitiers_alumni