Off to Harderwijk... main Hanseatic seaport trading city dating from 1200s... when the ZuiderZee was part of the north sea.
Amazing enigneers and strategic thinkers, these Dutch. 580 square miles was reclaimed from the ZuiderZee. 26% of the land in the Netherlands is below sea level.
Harderwijk has been called a Hanseatic city since 1252. The city joined the German Hanseatic League. Thanks to the numerous visits of merchants, bringing along trade products, the city was bustling with activity. Harderwijk became an influential city. It lies on what used to be the Zuiderzee shore (Southern Sea, now the IJsselmeer) and consequently its economy was strongly based on fishing and seafaring in general. That dramatically changed after 1932, when the Zuiderzee was cut off from the North Sea after a devastating flood.
Harderwijk, a gorgeous city on the edge of the Veluwe is a Hanseatic town that was fully involved in European trade as early as the 14th century. Ships from Harderwijk traded wool, skins, herring and wood with Germany, England and Flanders. In short, it is a city full of history and beautiful sights.
In 1231, the Count of Gelre gave Harderwijk city rights. The city developed quickly into a prominent trading town. It benefitted from its location along a number of important trade routes to Deventer, Elburg, Hattem, Kampen and cities along the Zuiderzee, Noordzee and the Baltic. Harderwijk even had its own trading post in Skanör in Sweden, where the largest fairs of the entire Baltic area were held.
Thanks to Harderwijk’s city rights, it could organise weekly markets and yearly fairs. At the time, the Smeepoortenbrink was used as a market square, where particularly the products which were brought and exported over land were traded. For example, blueberries, wood, sheets and beer from Amersfoort.
The Zuiderzee (Dutch: [ˌzœy̯dərˈzeː]; old spelling Zuyderzee) was a shallow bay of the North Sea in the northwest of the Netherlands, extending about 100 km (60 miles) inland and at most 50 km (30 miles) wide, with an overall depth of about 4 to 5 metres (13–16 feet) and a coastline of about 300 km (200 miles). It covered 5,000 km2 (1,900 sq mi). Its name means "southern sea" in Dutch, indicating that the name originates in Friesland, to the north of the Zuiderzee (cf. North Sea). In the 20th century the majority of the Zuiderzee was closed off from the North Sea by the construction of the Afsluitdijk, leaving the mouth of the inlet to become part of the Wadden Sea. The salt water inlet changed into a fresh water lake now called the IJsselmeer(IJssel Lake) after the river that drains into it, and by means of drainage and polders, an area of some 1,500 km2 (580 sq mi) was reclaimed as land. This land eventually became the province of Flevoland, with a population of nearly 400,000 (2011).
The construction in the early 20th century of a large enclosing dam (the Afsluitdijk) tamed the Zuiderzee. The creation of this dam was a response to the flood of January 1916. Plans for closing the Zuiderzee had been made over thirty years earlier but had not yet passed in parliament. With the completion of the Afsluitdijk in 1932, the Zuiderzee became the IJsselmeer, and large areas of water could be reclaimed for farming and housing. These areas, known as polders, were respectively the Wieringermeer, the Noordoostpolder, and Flevoland.
Historical map of the Netherlands (1658) with De Zuyder Zee'