In the summer of 1907, tribes of the Chaouia led a revolta against the application of terms in the 1906 Treaty of Algeciras in Casablanca, killing 9 European laborers working on the rail line between the port and a quarry in Roches Noires. The French responded with a naval bombardment of Casablanca from 5–7 August, and went on to occupy and "pacify" Casablanca and the Chaouia plain, marking the beginning of the French invasion from the west.