In 953, the archbishops of Cologne first gained noteworthy secular power, when bishop Bruno was appointed as duke by his brother Otto I, King of Germany.
With the intention of restoring as many historic buildings as possible, the successful postwar rebuilding has resulted in a very mixed and unique cityscape.
Cologne is a major cultural centre for the Rhineland; it hosts more than 30 museums and hundreds of galleries.
The archbishop nevertheless preserved the right of capital punishment.
Thus the municipal council (though in strict political opposition towards the archbishop) depended upon him in all matters concerning criminal justice.
The city functioned as the capital of the Roman province of Germania Inferior and as the headquarters of the Roman military in the region until occupied by the Franks in 462.
During the Middle Ages it flourished on one of the most important major trade routes between east and west in Europe.
Parts of the original Roman sewers are preserved underneath the city, with the new sewerage system having opened in 1890.
Early medieval Cologne was part of Austrasia within the Frankish Empire.
Roman imperial governors resided in the city and it became one of the most important trade and production centres in the Roman Empire north of the Alps. Maternus, who was elected as bishop in 313, was the first known bishop of Cologne.
The city was the capital of a Roman province until occupied by the Ripuarian Franks in 462.
The University of Cologne (Universität zu Köln) is one of Europe's oldest and largest universities.