Bernard Frénicle de Bessy (1605 - 1675) was a French mathematician. He solved many problems created by Fermat. He also discovered a taxicab number and many magic squares. Events April 13 - Tsar Boris Godunow dies - Feodor II accedes to the throne May 16 - Paul V becomes Pope June 1 - Russian troops in Moscow imprison Feodor II and his mother. ... Events January 5 - The Battle of Turckeim August 10 - Building of the Royal Greenwich Observatory began November 11 - Guru Gobind Singh becomes the Tenth Guru of the Sikhs. ... Pierre de Fermat Pierre de Fermat (August 17, 1601 – January 12, 1665) was a French lawyer at the Parliament of Toulouse and a mathematician who is given credit for the development of modern calculus. ... In mathematics, the nth taxicab number, typically denoted Ta(n) or Taxicab(n), is defined as the least number which can be expressed as a sum of two positive cubes in n distinct ways, up to order of summands. ... In mathematics, a magic square of order n is an arrangement of n² numbers in a square, such that the n numbers in all rows, all columns, and both diagonals sum to the same constant. ...