ABSTRACT.This contribution discusses the circumstances that led to the foundation of the great seaport of Alexandria by Alexander the Great and its subsequent development into the most important maritime emporium in the Mediterranean. It assesses the commercial, military and cultural importance of Alexandria in the development of the Ptolemaic kingdom of Egypt that lasted from 322 to 30 BC, and the even greater significance that it acquired within the Roman empire, as the centre of a maritime trading network that reached as far west as Britain and Ireland and as far east as India and Sri Lanka.

RÉSUMÉ.Cette contribution discute des circonstances qui ont amené à la fondation par Alexandre le Grand du majestueux port d'Alexandrie et comment il devint l'emporium le plus important de la Méditerranée. Elle analyse le rôle commercial, militaire et culturel d'Alexandrie dans l'essor du royaume ptolémaïque égyptien, de 322 à 32 av. J.-C., et mesure l'importance encore plus considérable qu'elle acquit au sein de l'empire romain, en tant que centre névralgique de tout un réseau de commerce maritime s’étendant aussi loin que la Grande-Bretagne et l'Irlande à l'ouest, et l'Inde et le Sri Lanka à l'est.

Throughout its history, Egypt has been a riverine civilization par excellence, with the Nile playing a primary role in all aspects of the Egyptians’ lives. Of the 6,700 km representing the total course of the Nile from its source in Lake Tanganyika to the delta on the southern coastline of the Mediterranean, 1,500 km run through the length of Egypt, with an average width of 750m. Moreover, in Antiquity it was navigable in both directions along its length at almost all times, as its currents flow from the south to the north while the prevailing winds blow in the opposite direction. In other words, the Nile served as Egypt's main highway, enabling water transport to link virtually all the inhabited areas of the country.