Historical Archive of the City of Cologne included copies of the protocols of the diets of the Hanseatic League. With the 1594 transfer, the Cologne archive became the most important repository of historical material concerning the Hanseatic League and thus concerning the history of Northern Germany in general, only matched by the municipal archives of Lübeck. On 27 February 1602, the city council ordered that books on jurisdiction and administration were to be systematically bought at the regularly held Frankfurt Book Fair. These were subsequently stored in the municipal archive and became the basis of the Cologne municipal library. The "Ratsbibliothek" was one of the few Cologne
Electorate of Cologne confused with the Roman Catholic Archdiocese of Cologne, which was larger and included suffragant bishoprics such as Liège and Münster over which the Elector-Archbishop exercised only spiritual authority (see map below). Cologne was the ancient Roman city of Colonia Agrippina in the province of Germania Inferior, and has been a bishop's see since Roman times. In 953, the archbishops of Cologne first gained noteworthy secular power, when Bishop Bruno was appointed as duke by his brother Emperor Otto I. To weaken the secular nobility, who threatened his power, Otto endowed Bruno and his successors in the bishop's see with the