Peat digging and floods developed the river Schermer into an inland lake with an open connection with the sea. Private investors started draining the lake between 1633 and 1635. For this huge job 52 windmills were used. The bottom of the Schermer lies more than 4 metres below sea level and windmills had to convey the water in several steps from one canal to the next.

The mills on the reclaimed land of the Schermer (in Dutch: ‘droogmakerij’ or ‘polder’) worked so well that people switched to electrical pumping stations for controlling water levels not before 1928.

There are still 11 windmills left in the Schermer, 5 of them nearby the village of Schermerhorn. One of them - the central mill in the PiP - nowadays houses Museummolen Schermerhorn . Visitors can see how a poldermill worked and how people used to live in it.