An important consequence of the French Revolution was the founding of the *Ecole Polytechnique* in Paris. There the country’s finest mathematicians, including Monge, Laplace, Lagrange and Cauchy, taught students destined to serve in both military and civilian capacities. The textbooks from the Ecole Polytechnique were later widely used in France and the United States.

*Pierre-Simon Laplace* (1749–1827) wrote an influential text on the analytical theory of probability and is also remembered for the *Laplace transform* of a function and *Laplace’s equation* in physics. His monumental five-volume *Traité de Méchanique Céleste* on celestial mechanics earned him the title of ‘the Newton of France’.

*Joseph Louis Lagrange* (1736–1813) was Euler’s successor at the court of Frederick the Great in Berlin. He wrote the first ‘theory of functions’, in the language of power series, and his *Méchanique Analytique* was a highly influential text on mechanics. In number theory he proved that every positive integer can be written as the sum of four perfect squares: for example, 79 = 49 + 25 + 4 + 1.

Shortly after the French Revolution, a commission was set up to standardise the weights and measures in France and introduce a metric system. The chairman of this commission was Lagrange and its members included Laplace and Monge.

*Augustin-Louis Cauchy* (1789–1857) was the most important analyst of the early 19th century. The calculus had proved to be on shaky foundations and he transformed the whole area by formalising the concepts of limit, continuity, derivative and integral. In addition, he almost single-handedly developed the subject of complex analysis; ‘Cauchy’s integral formula’ appears on the stamp.

*[France 1953, 1954, 1955, 1958, 1989, 1994]*