des Sciences et des Arts 1809: The findings of Lepère's survey, published in “Description de l’Égypte”, incorrectly reported an alleged 10-metre (32 feet 6 inches) difference in sea levels and a high cost, so the project was put on hold. 1833: Saint Simonians popularized the idea of constructing the canal. Prosper Enfantin, the leader of a sect of Saint Simonians, met with Ferdinand de Lesseps to conduct further surveys for the Suez Canal project. 1847: A second survey which included Robert Stephenson, Adrien Bourdaloue and Alois Negrelli, discovered that the first analysis was incorrect. It is possible to build a direct link between the Mediterranean Sea and the Red Sea. 30 November 1854: The former French consul in Cairo, Ferdinand Marie de Lesseps, obtained the first license for construction through an Act of Concession from Egypt's new viceroy, Said Pasha. 15 December 1858: De Lesseps established the international company "Compagnie Universelle du Canal Maritime de Suez"; initially the majority was controlled by French private holders. 25 April 1859: Construction officially started, with 20,000 fellahin forced to work. 17 November 1869: Official opening of the Suez Canal. Empress Eugénie of France attended the opening ceremony and celebrations. 1873: The International Commission of Constantinople established the Suez Canal Net Ton and the Suez Canal Special Tonnage Certificate 1875: The British purchase nearly half of the Suez Canal company's stock. 1882: British military forces invaded Egypt. The canal was still managed by the privately owned Suez Canal Company. 29 October 1888: The Convention of Constantinople was signed. Its main purpose was to guarantee free passage to merchant ships and regulate the transit of military warships. 26 January to 4 February 1915: the Raid on the Suez Canal occurred as the Ottoman Army attacked the Suez Canal which was under the protectorate of the British Empire. 14 November 1936: Following a new treaty, Britain pulled out of Egypt, but established the 'Suez Canal Zone' under its control. 10 January 1950: Passenger tariffs are abolished. 13 June 1956: Suez Canal Zone was restored to Egyptian sovereignty, following British withdrawal of about 90,000 troops and years of negotiations. 26 July 1956: the Egypt president Nasser nationalised the Canal, previously under the control of a Franco-British company. 29 October 1956: Israel proceeded with the invasion of the Egyptian portion of the Sinai, marking the beginning of the Suez Crisis. 31 October 1956 to 24 April 1957: the