At an early date Christianity came to
Cologne with the Roman soldiers and traders. According to
Irenaeus of Lyons, it was a bishop's see as early as the second century. However,
Saint Maternus, a contemporary of
Constantine I, is the first historically certain bishop of Cologne. As a result of its favourable situation, the city survived the stormy period around the
fall of the Western Roman Empire. When the
Franks took possession of the country in the fifth century, it became a royal residence. On account of the services of the bishops to the
Merovingian kings, the city was to have been the metropolitan see of
Saint Boniface, but
Mainz was chosen, for unknown reasons, and Cologne did not become an archbishopric until the time of
Charlemagne. The city suffered heavily from
Viking invasions, especially in the autumn of 881, but recovered quickly from these calamities, especially during the reign of the
Ottonian emperors. From the mid-13th century, the
Electorate of Cologne—not to be confused with the larger Archdiocese of Cologne—was one of the major ecclesiastical principalities of the
Holy Roman Empire. The city of Cologne as such became a free city in 1288 and the archbishop eventually moved his residence from
Cologne Cathedral to
Bonn to avoid conflicts with the Free City, which escaped his jurisdiction. From the 1583 appointment of
Ernest of Bavaria as archbishop to the 1761 death of
Clemens August of Bavaria, the archbishop was invariably a junior son of the Bavarian branch of the
House of Wittelsbach. After 1795, the archbishopric's territories on the left bank of the
Rhine were occupied by
France, and were formally annexed in 1801. The
Reichsdeputationshauptschluss of 1803 secularized the rest of the archbishopric, giving the Duchy of Westphalia to the
Landgraviate of Hesse-Darmstadt. As an ecclesial government, however, the archdiocese remained (more or less) intact: while she lost the left bank including the episcopal city itself, Cologne, to the new
Diocese of Aachen established under Napoleon's auspices, there still remained a substantial amount of territory on the right bank of the Rhine. After the death of the last Elector-Archbishop in 1801,
the see was vacant for 23 years, being governed by
vicar capitular Johann Herrmann Joseph v. Caspars zu Weiss and, after his death, by Johann Wilhelm Schmitz. In 1821, the archdiocese regained Cologne and the right bank of the Rhine (though with a new circumscription reflecting the Prussian subdivisions) and, in 1824, an archbishop was established there again. It remains an archdiocese to the present day, considered the most important one of Germany. ==Finances==