Baltic maritime trade began in the late Middle Ages and would continue to develop into the early modern era. During this time, ships carrying goods from the Baltic and North Sea passed along the Øresund, or the Sound, connecting areas like the Gulf of Finland to the Skagerrak. Over a period of 400 years, maritime powers in the east and west struggled to control these markets and the trade routes between them. The Baltic system can be explained beginning with the German Hanseatic era and ending with the Great Nordic Wars.