François Viète was born in the year 1540 in Fontenay-le-comte, in France, and died on December 13, 1603 in Paris. Passionate about algebra, this French mathematician was responsible for introducing the first systematized algebraic notation, as well as contributing to the theory of equations. He became known as the Father of Algebra. Although best known as a mathematician, he was also one of the best cipher specialists of all time.
In the late 16th century, the Spanish empire dominated much of the world, so Spanish agents had to communicate using a hard-to-understand figure. It was a figure composed of over 500 characters, used by King Philip II of Spain during his war in defense of Roman Catholicism and the French Huguenots. Some messages from Spanish soldiers were intercepted by the French and ended up in the hands of King Henry IV of France. The king delivered these Spanish messages to the mathematician Viète, hoping that he would decipher them.
The mathematician succeeded and kept it a secret. However, two years later, the Spanish discovered their deed. King Felipe of Spain, believing that such a complex figure could never be broken, and being told that the French knew his military plans, went to complain to the Pope that black magic was being used against his country.
In algebra, it was Viète who adopted vowels for the unknowns, consonants for known numbers, graphs for solving cubic and square (or 4th degree) equations, and trigonometry for higher degree equations. Viète, which also simplifies trigonometric relations, can be considered a precursor of analytic geometry.
It was he who, making numerous simplifications in solving the equations, paved the way for Descartes, Newton, among others. Your book "Isagoge in artem analyticum"(Tours, 1591) is the oldest work on symbolic algebra. A first appendix has been added,"Specious Logistice"in which it dealt with addition, multiplication, and showed how to raise a binomial to the sixth power. In the second appendix,"Zetetica", explained the resolution of equations. In other works it dealt with the theory of equations and the resolution of various numerical equations.