The mission of the Belvedere Archive centers on collecting, archiving, and documenting. The collection of in-house records makes it possible to track the more than one-hundred-year history of the museum since the foundation of the Modern Gallery in 1903. The artist documentation contains extensive material on more than 20,000 – mostly Austrian – artists that is continuously updated and can be searched via an online database. In addition to the historical archives, the collection also includes the estates of Hans Ankwicz-Kleehoven (1883–1962) and Rudolf Schmidt (1894–1980), the Neue Galerie archive, and the Waldmüller archive. The estates of Austrian artists such as Franz Barwig, Bettina and Georg Ehrlich, Johann Peter Krafft, H+H Joos, Emilie Mediz-Pelikan, Trude Waehner, and Alfred Zoff are also available for research.