An inland sea called the Waterwolf
For centuries, where Hoofddorp now stands, there was no land, only water. The Haarlemmermeer was a vast inland sea between Amsterdam, Haarlem and Leiden, formed by the merging of smaller peat lakes whose shores had been eaten away by storm and peat extraction. In a westerly gale, waves crashed against the shoreline villages; in a southwesterly storm, dykes on the eastern side came under threat. The unruly body of water earned the nickname Waterwolf, because it literally devoured pieces of shore.
As early as the seventeenth century, the hydraulic engineer Jan Adriaensz. Leeghwater drafted a detailed plan to drain the lake using windmills. The technology of his day was not equal to it — hundreds of mills would have been needed — but the idea kept circulating. Only in the nineteenth century, with the rise of the steam engine, did draining become feasible.
The immediate trigger was a series of major storms. In November 1836 water was driven up to the gates of Amsterdam; in December of that same year, Leiden was flooded. King William I ordered the lake to be drained once and for all.