text: Being a free city, Sélestat attracted settlers from the region who sought protection, freedom and a thriving economic environment. The first city wall, which had become too constricting, was replaced in 1280, and a third wall had to be erected in the 16th century as the city grew. At the end of the Middle Ages, the population was estimated at between 5,000 and 6,000. It was then the fourth largest Alsatian town after Strasbourg (18,000), Colmar and Haguenau (6,000 each). The local economy reached its zenith around 1500. It was centered on shipping and trade (mainly hay, cereals, wine, fish, glass, iron and salt). As the road network was poor and dangerous, goods transited via the Ill river.
  Decline
  The decline of the town started in the 1520s, when the humanist school lost its former influence. The troubles surrounding the Protestant Reformation brought instability and unrest to the region. The town experienced the German Peasants' War in 1525 and its convents were sacked by a mob in 1534. During the same period Sélestat lost its pre-eminence in the Decapolis because the city of Mulhouse left the alliance in 1515 and was replaced by Landau in 1521, moving the geographical centre of the alliance to the north.
  During the 17th century, Alsace was one of the main battlefields of the Thirty Years War. Sélestat was seized by the Swedes in 1632 after a month-long siege. They surrendered the town to their French allies two years later. The local population long remained predominantly faithful to the House of Habsburg. The Peace of Westphalia (1648) formalised the annexation of the Decapolis by France. Sélestat was briefly occupied by the Germans during the Franco-Dutch War in 1674. The Treaties of Nijmegen (1679) that ended the war also abolished the Decapolis.