Gallia Narbonensis was a Roman province located in what today are Occitania and Provence, in Southern France. It was also known as Provincia Nostra, because it was the first Roman province north of the Alps, and as Gallia Transalpina, distinguishing it from Cisalpine Gaul in Northern Italy. It became a Roman province in the late 2nd century BC. Gallia Narbonensis was bordered by the Pyrenees Mountains on the west, the Cévennes to the north, the Alps on the east, and the Gulf of Lion on the south; the province included the majority of the Rhône catchment. The western region of Gallia Narbonensis was known as Septimania. The province was a valuable part of the Roman Empire, owing to the Roman civitas of Massilia, its location between the Spanish provinces (Hispania) and Rome, and its economic output.