Presidential Palace is the elegant classicist latest version of a building that has stood on the Krakowskie Przedmieście site since 1643. Over the years, it has been rebuilt and remodeled many times. For its first 175 years, the palace was the private property of several aristocratic families. In 1791 it hosted the authors and advocates of the Constitution of May 3, 1791. source: http://en.wikipedia.org/wiki/Presidential_Palace,_Warsaw