Rouen or [ʁuɑ̃]) is a city on the River Seine in northern France. It is the capital of the region of Normandy. Formerly one of the largest and most prosperous cities of medieval Europe, the population of the metropolitan area is now 655,013. Rouen was the seat of the Exchequer of Normandy during the Middle Ages. It was one of the capitals of the Anglo-Norman dynasties, which ruled both England and large parts of modern France from the 11th to the 15th centuries. People from Rouen are known as Rouennais.