From the end of the 16th century onward, the famous plan of the three canals, extended
to almost triple the size of the city by some 800 hectares, was under discussion. Several voices
were raised in opposition. In 1607, the project was approved, and it was begun in 1609. In the
course of half a century, the Herrengracht, the Kaisergracht, and the Prinsengracht were
completed in turn, as well as numerous radial streets and canals which linked them. The
principle of the star-shaped baroque fortress was adapted to the canals. The city finally lit on this
brilliant idea after centuries of transforming fortification moats into shipping canals every time the
city expanded. The city was once more ringed round by fortifications some 8 kilometers in length,
strengthened by twenty-six bastions. A highly developed system of water gates and locks served
ship traffic. The Amstel was pressed into the city’s service for all time.