Demographics of Cologne and on 1 April 1888 ended in a first major incorporation. The territorial expansion, beginning in the late 19th century, were significant marks for the city's population growth. Major communal reorganizations took place in 1910, 1914, 1922 and 1975. Demographics of Cologne Cologne () is Germany's fourth-largest city and the largest city in the Rhineland. As of 31 December 2011, there were officially 1,017,155 residents. The city is center of the Cologne/Bonn Region with around 3 million inhabitants (including the neighboring cities of Bonn, Hürth, Leverkusen, and Bergisch Gladbach). The walls of Colonia Agrippina covered an area of 96.8 hectares,
Cologne City Hall immediacy as a free imperial city. In 1388 Pope Urban VI signed the charter for the University of Cologne, Europe's first university to have been established by citizenry. On 14. September 1396 the constitution of Cologne came into effect and the Cologne gaffs and guilds ("Gaffeln" and "Zünfte") assumed power in the council. Following the tradition of Roman consuls, the council was headed by two elected Burgomasters (Mayors) until the year 1797, when council and constitution were replaced by the Napoleonic and later code civil. Since 1815 the city council is led by one Oberbürgermeister (Lord Mayor). During the bombing