The construction went on from 1620 to 1623, and the work was managed by Gdańsk’s prominent architect, Jan Strakowski. The Stone Sluice was built as a section of Gdańsk’s fortifications, so it had to match the other buildings. It has two stone cofferdams, at the ends of which stand four turrets called the Virgins. Equipped with two lunettes called the Pigs’ Heads, it had two pairs of dams, regulating the Motława’s water level. The Stone Sluice, besides its regulatory function, also performed other important tasks for the city. Locating a mill here prevented Gdańsk from being completely dependent upon the Great Mill on Radunia, which could be blockaded in the event of warfare, and the ability to regulate water allowed the flooding of Żuławy Gdańskie and the protecting of the city of Gdańsk if it were threatened.