Hanseatic cities are cities that were part of the so-called Hanseatic League. The network was an association of traders and affiliated cities with the aim of promoting and protecting trade. The network originated in Germany in the mid-12th century, mainly around the Baltic Sea. Later, towns from other northern European countries joined, including Dutch towns. Until the beginning of the sixteenth century, the trade association ensured much trade success and prosperity for the various Hanseatic cities.