There was a first settlement about 1200 A.D., which became a city in 1284. In the following century, Flensburg became the economic centre of the Duchy of Schleswig. In 1409 there were battles between people of the Duchy of Holstein and the Danish crown about the control of Schleswig. In 1412 and 1500 there were bad plagues in Flensburg. In 1485, there was a big fire in the city.