As the city's livelihood depended from the first on its river-borne trade, commercial activity naturally centred on the place where the goods were landed. This was the place de Grève on the Right Bank , where the Hôtel de Ville now stands. Marshy ground originally, it was gradually drained to accommodate the business quarter. The Right Bank continues to be associated with commerce and banking today.

 

The Left Bank 's intellectual associations are similarly ancient, dating from the growth of schools and student accommodation round the two great monasteries of Ste-Geneviève and St-Germain-des-Prés. In 1215, a papal licence allowed the formation of what gradually became the renowned University of Paris , eventually to be known as the Sorbonne , after Robert de Sorbon, founder of a college for poor scholars.

To protect this burgeoning city, Philippe Auguste (king from 1180 to 1223) built the Louvre fortress and a defensive wall, which swung south to enclose the Montagne Ste-Geneviève and north and east to encompass the Marais. The administration of the city remained in the hands of the king until 1260, when St Louis ceded a measure of responsibility to the leaders of the Paris watermen's guild, whose power was based on their monopoly control of all river traffic