Catholic theologian, decided to write a 700 page book to prove that it was not Leo X but Martin Luther who was the Antichrist. Aside from these most interesting situations, Stifel did make some real contributions to mathematics. His most famous work is the book Arithmetica Integra. In this book is one of earliest logarithm tables, which is very similar to the ones we use today. Stifel invented logarithms using a method unique to the method that Napier used. Probably the most important contribution Stifel made was in that he was the first European mathematician to use the addition, subtraction, and square root symbols: +, -, and . Stifel also made other contributions to algebra and basic arithmetic. Michael Stifel was, in the kindest terms, an eccentric mathematician. His work as helped the development of algebra, and he helped to shape modern mathematics. However his ideas on the end of the world and about Leo X most likely overshadow the good he has done. A page from Arithmetica ntegra Another page from Arithmetica Integra Roberval Gilles Personne Roberval was born in Senlis, France, on August 10, 1602. He was a French mathematician who died on October 27, 1675, in Paris. He came from a family of simple farmers with a simple way of life. Since his family was poor, Roberval had no official schooling. His family taught him until he left home sometime before his fourteenth birthday. At the age of fourteen, Roberval's interest in mathematics was born. Roberval traveled all over France earning money by giving private lessons. He also talked with many professors at universities about many advanced topics. Once while Roberval was in Bordeaux, he met Fermat. Because of this meeting, Roberval was selected to participate in the group that met with Mersenne. Roberval arrived in Paris in 1628 where he met with the group. He took a particular interest in Mydorge, Etienne Pascal, and Blaise Pascal. It is interesting to note that even with the talen...
