Investing in water
At the end of the 16th century the sea threatened to engulf large parts of the peat area north of the IJ within the province of Holland. Especially high water levels and strong wind caused the peat to wash away and Beemster Lake to expand. A growing need for good agricultural land developed with the population increase at the beginning of the 17th century. So investing in land seemed to be an ideal way to secure capital. Furthermore, wealthy city dwellers required space to build their country houses. By that time, it was considered technically feasible to drain lakes or pools by means of windmills and therefore some merchants took the initiative to drain Beemster Lake. They were granted permission by the Dutch court and soon were able to convert their investment in water into firm clay.

Land below sea level
Work commenced in 1607. A ring-dyke was constructed, a ring canal was dug and drainage mills were built. Jan Adriaenzn Leeghwater (1575-1650) supervised the construction of the mills and the draining at the request of the dyke builders. The job was finished in 1612: a total of 43 mills had been deployed to drain the lake. Today the reclaimed land lies approximately 3.5 metres below sea level. Its soil is fertile clay. The success of the Beemster induced the impoldering of dozens of other lakes and pools in the entire low-lying part of the Netherlands and even abroad, mainly in first half of the 17th century.