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
Cologne was responsible for military operations in Bonn, Siegburg, Aachen, Jülich, Düren, and Monschau. Cologne was home to the 211th Infantry Regiment and the 26th Artillery Regiment. The Allies dropped 44,923.2 tons of bombs on the city during World War II, destroying 61% of its built up area. During the Bombing of Cologne in World War II, Cologne endured 262 air raids by the Western Allies, which caused approximately 20,000 civilian casualties and almost completely wiped out the central part of the city. During the night of 31 May 1942, Cologne was the target of "Operation Millennium", the first 1,000 bomber