Districts of Cologne within city limits), while 174,87 km² (43.2 percent) lie right of the Rhine. In regard to population, Cologne is the largest city in the state of North Rhine-Westphalia and the fourth largest city in Germany. Since the city's foundation in 38 BC, Cologne grew through numerous extensions and incorporation of surrounding municipalities. Since the construction of the Medieval wall in 1180, the area of the old imperial city of Cologne has not changed for more than 600 years and was only extended over the old city walls in 1794, just short before the arrival of French troops and Cologne's incorporation
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