Imperial City of Cologne

The German city of Cologne was founded in the 1st century as the Roman Colonia Claudia Ara Agrippinensium. It was taken by the Franks in the 5th century and became an important city of Medieval Germany, the seat of an Archbishop and a Prince-Elector. As the Free Imperial City of Cologne it was one of the centers of the Hanseatic League in the early modern period.

Most of the city was destroyed in the bombing of Cologne in World War II, so it was of limited importance in post-war West Germany. It had returned to its pre-war population by 1959, by which time Düsseldorf was the political center of the state of North Rhine-Westphalia, and Bonn was the (provisional) capital of the Federal Republic. In the late 20th century, Cologne grew into a center of the sprawling Rhine-Ruhr metropolitan area, with some 12 million inhabitants, just over one million of whom live in Cologne proper (as of 2012), making the city the fourth largest in Germany (after Berlin, Hamburg and Munich).

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.

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