Tensions between the Hassan and the Zawaya had also been exacerbated by an economic crisis; the two groups had previously complemented each other, with the Hassan being largely nomadic, whilst the Zawaya were agriculturalists along the Senegal. The French had established a trading post on the Atlantic at Saint-Louis in 1659, and this was in turn pulling the trade along the Senegal towards the Atlantic, disrupting the traditional trade along the Senegal. In particular the monopoly of Saint-Louis was depriving Moors of the slave labour they had relied on for centuries as well as the cereals from the agriculturalists along the Senegal. The nomadic desert groups north of the Senegal were heavily reliant on these cereals for survival. Berber society was then caught between the southern movement of the Hassan Arabs and the loss of trade due to Saint-Louis.