Timeline 1789Born on 21 August in Paris, five weeks after the fall of the Bastille. 1794During the Terror, the family takes refuge in Arcueil, next door to Laplace. 1805Enters the École Polytechnique, second in the entrance examination. 1810Goes to Cherbourg as an engineer on Napoleon’s military harbour. 1813Returns to Paris in poor health and proves Fermat’s polygonal number theorem. 1816Appointed to the Academy of Sciences by royal decree, in place of Monge. 1821Publishes the Cours d’analyse of the École Polytechnique. 1825Presents the memoir on integrals between imaginary limits. 1830Refuses to swear allegiance to Louis-Philippe and goes into exile. 1833In Prague, becomes tutor to the Duke of Bordeaux, grandson of Charles X. 1838Returns to Paris. 1848The new republic abolishes the oath; the following year he takes up the chair at the Sorbonne. 1857Dies on 23 May at Sceaux, aged 67. A child of the Revolution Augustin-Louis Cauchy was born in Paris on 21 August 1789. The Bastille had fallen on 14 July, and his father, Louis-François Cauchy, was a senior official of the Paris police, an Ancien Régime post that became dangerous overnight. In 1794, during the Terror, the family fled to their country house in Arcueil, south of the city. There they knew hunger and poverty; Augustin was a frail child, and poor health stayed with him all his life.