The Oslo University Hospital is the largest hospital in Scandinavia, with a work force of around 25,000. It was established on 1 January 2009, by the merger of three of the university hospitals in Oslo: Rikshospitalet (The National Hospital), Ullevål University Hospital (founded 1887), and Aker University Hospital (founded 1895). It is affiliated with the Faculty of Medicine of the University of Oslo (founded in 1811). Bjørn Erikstein has been CEO since 2011.