Archdiocese of Cologne

Christianity reached Cologne long before it had an archbishop. Saint Maternus, attested at a Rome council in 313 as a contemporary of Constantine, is the earliest historically certain bishop of the city, presiding over an ordinary diocese for nearly five centuries. What changed its rank was Charlemagne's reorganization of the church in his expanding empire. In 795 he elevated Cologne to an archdiocese and appointed his own chaplain, Hildebold, who was already serving as its bishop, as the new archbishopric's first archbishop.

The promotion was not merely honorary. Hildebold received metropolitan authority over a cluster of suffragan sees across the Lower Rhine and further north, including Tongres-Liege and Utrecht, making Cologne the senior church of a genuinely large ecclesiastical province rather than a single city's bishopric. That structure proved durable. Cologne remained a metropolitan see governing multiple dioceses for the rest of the medieval period and into the modern one, and the office Hildebold first held grew, by the mid-13th century, into something considerably larger than a spiritual post: its holders became prince-electors of the Holy Roman Empire, ruling a temporal territory, the Electorate of Cologne, alongside their religious authority, a dual role that lasted for roughly five and a half centuries after Hildebold's own appointment before Napoleon-era reforms finally separated the two.

The Archdiocese of Cologne now publishes an annual financial report stating its balance sheet total to the euro, 4.4 billion euros as of the end of 2024, and it does so under no legal compulsion to. As a body governed by public law under Article 137 of the Weimar Constitution and the 1933 Reichskonkordat, it is not required by the German state to publish diocese-level financial statistics at all, a gap that let German dioceses keep their reserves, investments and property holdings essentially confidential for decades.

What broke that silence was not a change in the law but a scandal in a much smaller diocese. Bishop Franz-Peter Tebartz-van Elst of Limburg, appointed in 2008, oversaw a new episcopal residence whose cost overran its original budget roughly sixfold, reaching about 31 million euros by the time the story broke in 2013, much of it drawn from the diocese's own reserves. The public reaction was fierce enough that the Vatican accepted his resignation in 2014, and the embarrassment rippled well beyond Limburg itself: at least six of Germany's twenty seven Catholic dioceses at the time responded by voluntarily opening their books for the first time, revealing reserves that had never before been disclosed publicly. Cologne's own detailed annual reports, with their euro-precise balance sheets and equity figures, are a direct descendant of that reckoning, a transparency the law still does not require but that a bishop's excess made politically unavoidable to withhold.