Dusseldorf The University Library has an extensive collection of genealogical , originating probably down to the 18. century goes back . interest and study of historical sources of all kinds to the acquisitions of the “ Royal State Library ” in the second half of the 19. largely determined century . Unter Theodor Joseph Lacomblet, the Rhenish Church historian , Archivar und Bibliothekar, the care of the story and its auxiliary sciences was deliberately moved into the center .