Krefeld is well-known in architectural circles through the buildings designed for the silk barons Lange and Esters at the end of the 1920s by star architect Mies van der Rohe. Today Haus Lange and Haus Esters are internationally renowned art museums. However, the heyday of silk production also left its mark on the city centre. The breeding ground for this prosperity was the neutrality agreement concluded in 1607 which granted Krefeld far-reaching religious freedom. Many religious refugees settled in the city including Mennonite craftsman families such as the von der Leyens who later became important representatives of the silk industry. Today's town hall is the former city palace of the von der Leyen-familiy built by the architect Martin Leydel in 1794. The town centre underwent five enlargements prior to 1766. In 1819 the town planner Adolph von Vagedes surrounded the centre with a classicistic group of four, still existing, roads set at right angles to one another, thereby defining the compact core of the inner city. Together with modern buildings such as the Behnisch-House, which was created in 2002, a large number of other architecturally significant buildings, designed by well-known architects including Karl Buschhüter and Bernard Pfau, can be discovered in Krefeld. Information about Krefeld's building culture can be obtained in the series of brochures "Architektur entdecken" ("discovering architecture)".