The founding building of the Zurich Polytechnic was constructed between 1860 and 1864 according to the plans of Gottfried Semper. The building combined collection and institute rooms with lecture halls; subsequently, this representative multifunctional building became the ideal model for a polytechnic main building. Numerous subsequent buildings varied in scale and architectural decoration, yet the forms of the Italian Renaissance and patterns of spatial hierarchies and access remained largely binding. In the 20th century, the building underwent two significant changes: during World War I, it was expanded and reshaped by Gustav Gull. With the concept of renewing and completing Semper's building, Gull remained in the tradition of the artisan and scientifically-minded idealism of the 19th century. The renovations occurred during the progressive and technology-optimistic boom years of the 1960s and 1970s.