The history of Cologne covers over 2000 years of urban history. In the year 50, Cologne was elevated to a city under Roman law and named "Colonia Claudia Ara Agrippinensium"; since the Frankish rule it is known by derivatives of simply Colonia, including German (later ) and French (borrowed into English) Cologne. The city became an influential merchant stronghold in the early Middle Ages due to its location on the Rhine, which allowed the most seasoned Cologne wholesalers to control the flow of goods from northern Italy to England. The archbishops promoted the perception of "Holy Cologne" when they developed the city to the capital of their Electorate of Cologne; to this end, they had both the semicircular city wall and the Gothic Cologne Cathedral built as a demonstration of power. In the 15th century, Cologne was able to shake off archiepiscopal rule and, as a Free Imperial City, enabled the burgher ruling class to achieve great splendor, visibly documented by the Cologne School of Painting. After the Thirty Years' War, however, the city's development stalled. Only after French occupation when in 1815, Cologne was incorporated into Prussia, the city experienced a steady upswing borne by industrialization. In 1880, the cathedral was completed as a national monument of German imperial unity providing the city with its well-known landmark. Extensive devastation in the Second World War was followed by decades of reconstruction, which only slowly restored Cologne to its emblematic urban panorama on the Rhine through the efforts of urban repair. Today with more than one million inhabitants, Cologne is the fourth largest city in Germany. It is primarily marketed as an event city, with Cologne Carnival being perceived as the biggest tourist attraction.
Demographic history of Cologne
In the time of Roman Late antiquity, the cultural development in northwestern Europe west of the Rhine was embodied by a network of urban settlements. Most important towns in the Rhineland were Trier, which served as imperial residence of the Western Roman Emperor from 293 to 395, and Cologne, where five Roman trunk roads intersected with the Rhine, also then used as a water transport route. When the Franks formed their kingdoms after the decline of Roman power, the Roman induced urban settlements in the Rhineland largely perished. Only a few places — such as Trier, Cologne and Mainz — remained continuously inhabited within the Roman urban scope, however with a significantly reduced population. Cologne, which had been inhabited by up to 20,000 people in Roman Late Antiquity,Gerhard Curdes, Markus Ulrich: Die Entwicklung des Kölner Stadtraumes, Der Einfluß von Leitbilder und Innovationen auf die Form der Stadt. Dortmund 1997, p. 73ff. counted in the year 700 about 3,000 settlers and was thus after Trier (5,000) the second largest town in the Rhineland. Further west, the urban tradition survived in more numerous places, none of them having gathered significantly more inhabitants. This applies, among others, to Tours, Rouen, Reims (5,000 each) and Paris (3,000). The largest cities in Western Europe were Rome (44,000) and Milan (21,000).E. Buringh, 2020, "European urban population, 700 - 2000", https://doi.org/10.17026/dans-xzy-u62q, DANS Data Station Social Sciences and Humanities, V1
In the following centuries, dynamic growth of Cologne was driven by enhanced merchant activities on river Rhine; in addition, the town became seat of an influential archbishop. In the year 1000, the city with 10,000 inhabitants was among the three largest cities in northwestern Europe, after Paris (15,000) and Rouen (12,000). From 1000 to 1200, Cologne experienced further steep growth and quadrupled its population to 40,000.E. Buringh, 2020, "European urban population, 700 - 2000," https://doi.org/10.17026/dans-xzy-u62q, DANS Data Station Social Sciences and Humanities, V1 This expansion was mirrored by an intensified church building in romanesque style known as the "great century of Cologne church architecture"Werner Meyer-Barkhausen: Das große Jahrhundert Kölnischer Kirchenbaukunst 1150 bis 1250, Cologne 1952 from 1150 to 1250.
In the Middle Ages and the early modern period, Cologne was consistently among the 30 largest cities in Western Europe. This indicates the importance of the merchant center on the Rhine, because, in these periods, the number of inhabitants can be read as a good indicator of economic prosperity.J. Bradford De Long, Andrei Shleifer: Princes and Merchants: European City Growth before the Industrial Revolution, National Bureau of Economic Research Working Paper No. 4274, Cambridge, February 1993 However, Cologne could hardly ever count itself among the leading metropolises in Western Europe. Around 1200, the archbishops expanded the city and made it the capital of their sphere of influence;Joachim Deeters: Vom Bau der Großen Mauer um Köln 1180, Neue Überlegungen zu einem alten Problem der Kölner Stadtgeschichte; in: Geschichte in Köln, Zeitschrift für Stadt- und Regionalgeschichte 69 (2022), pp. 33-49, here p. 49 with a population of 40,000, Cologne reached a size comparable to London and Paris and was thus among the 10 largest cities in Western Europe.
In the following three centuries, the Rhine city, as a merchant center, unfolded a tightly linked trading network that included the Hanseatic towns of the Baltic Sea, in the west London and Bruges, but also trading places such as Bordeaux and Leipzig, and in the south the centers of Milan and Venice. Within this network, Cologne developed a strong but not dominant position. While other cities continued to grow, Cologne never exceeded a population of about 45,000 until the end of the 18th century. As early as 1300, the Flanders city of Ghent became a mercantile center of cloth industry with 64,000 inhabitants, and thus the largest city in the northwest; in those years Paris already reached a population of 75,000 and Milan, as a commercial metropolis, had about 100,000 inhabitants.E. Buringh, 2020, "European urban population, 700 - 2000", https://doi.org/10.17026/dans-xzy-u62q, DANS Data Station Social Sciences and Humanities, V1
When Cologne was elevated to Free Imperial City status at the end of the 15th century, it was the largest city in the Holy Roman Empire, but only one of several important trading centers between the Scheldt and Elbe. Among them were in Flanders the cities of Ghent (45,000), Bruges and Tournai (35,000 each), as well as Brussels (33,000) and Antwerp (30,000), and in the southern part of Germany the cities of Nuremberg (38,000) and Augsburg (30,000); of the Hanseatic cities, the most important were Hamburg, Gdańsk (Danzig) (30,000 each) and Lübeck (25.000). The dominant commercial places of Western Europe were Milan and Venice (100,000 each); among the political centers, the most numerous population had Naples (125,000), Paris (94,000), and London (50,000).E. Buringh, 2020, "European urban population, 700 - 2000," https://doi.org/10.17026/dans-xzy-u62q, DANS Data Station Social Sciences and Humanities, V1
In the second half of the 16th century, trade flows increasingly shifted away from the Rhine to sea routes, diminishing Cologne's influence on the long-distance trade network. Cologne did continue to maintain its population of around 40,000 until the 18th century. This is remarkably enough given the belligerent and epidemic vicissitudes that hit other commercial centers. Nevertheless, the city of Cologne became relatively less important and its commercial sphere of influence was mainly reduced to the regional environment. Antwerp established itself around 1560 with 100,000 inhabitants as the commercial metropolis of the northwest.Fernand Braudel: The perspective of the world, London 1984, p. 143
The military conflicts of the Thirty Years' War were by and large beneficial for Cologne because it was considered impregnable and could benefit from the arms trade; in any case, the Rhine city did not suffer a blow like the cities of Nuremberg, Augsburg or Magdeburg, all three until then on a steep growth path. Cologne had little share in the Atlantic trade that began in the 17th century, which made Amsterdam (180,000) to the Netherlands trading metropolis and Hamburg (70,000) the largest German trading city. Thus in 1700, Cologne dropped out of the top 30 list of largest cities in Western Europe. Increasingly, population growth was absorbed by the political centers such as London (575,000), Paris (500,000), and Vienna (114,000), all on the way to a form of modern European metropolises. Berlin (50,000) still had its dynamic growth ahead of it, and achieved the status of a major urban center ("Grossstadt") only in 1763, when its population exceeded permanently 100,000 inhabitants.E. Buringh, 2020, "European urban population, 700 - 2000", https://doi.org/10.17026/dans-xzy-u62q, DANS Data Station Social Sciences and Humanities, V1
With the onset of industrialization, Cologne doubled its population between 1810 (45,000) and 1846 (90,000) and was in 1850 the sixth largest city in Central Europe after Berlin, Vienna, Hamburg, Prague and Breslau. In the same period however, London was already inhabited by more than 2 million people, and Paris population surpassed 1 million. Industrialization as the driver of city size was exemplified by the British industrial cities Liverpool, Glasgow and Manchester, all exceeding 300,000 inhabitants by 1850.E. Buringh, 2020, "European urban population, 700 - 2000," https://doi.org/10.17026/dans-xzy-u62q, DANS Data Station Social Sciences and Humanities, V1
During the entrepreneurial boom of the Gründerzeit, Cologne benefited from the railroad network that crossed the Rhine in the heart of the city. Cologne managed to increase its population — also through generous expansion of the urban area — to 650,000 by World War I. After the war, Cologne was one of the four largest cities in the German Empire, after Berlin (1.9 million) and Hamburg (985,000) and about equal with Munich (630,000). In 1939, more than 770,000 people lived in Cologne. The city was able to recover after the extensive destruction in World War II and grew by more than 30% between 1939 and 1975 sustained by a very diversified economic structure. In 2000, Cologne, as megacity with more than one million inhabitants, was Germany's fourth-largest city after Berlin, Hamburg, and Munich; in northwestern Europe, Cologne ranked sixth after London, Paris, Hamburg, Brussels and Copenhagen. When considering Western Europe (EU in 2000 borders), the Rhine city was among the 20 largest metropolises.E. Buringh, 2020, "European urban population, 700 - 2000," https://doi.org/10.17026/dans-xzy-u62q, DANS Data Station Social Sciences and Humanities, V1
Early history Roman period
In 39 BC the Germanic tribe of the Ubii entered into an agreement with the forces of the Roman General Marcus Vipsanius Agrippa and settled on the left bank of the Rhine. Their headquarters was Oppidum Ubiorum (settlement of the Ubii) and at the same time an important Roman military base. In 50 AD the Cologne-born Agrippina the Younger, wife of the Emperor Claudius, asked for her home village to be raised to the status of a colonia — a city under Roman law. It was then renamed Colonia Claudia Ara Agrippinensis (colony of Claudius and the altar of Agrippina), shortened to Colonia Agrippina (Colony of Agrippina). In 80 AD the Eifel Aqueduct was built. It was one of the longest aqueducts of the Roman Empire, delivering 20,000 cubic metres of water to the city every day. Ten years later, the colonia became the capital of the Roman province of Lower Germany, Germania Inferior, with a total population of 45,000 people occupying 96.8 hectares.J.C. Russell, "Late Ancient and Medieval Population", in Transactions of the American Philosophical Society, vol. 48, part 3, table 89.