Oslo is a county and municipality, as well as the capital and largest city in Norway. Oslo was established as a municipality on 1 January 1838. Founded around 1048 by King Harald III “Hardraade” of Norway, the city was largely destroyed by fire in 1624.
The Danish–Norwegian king Christian IV moved the city, rebuilding it closer to Akershus fortress, as Christiania (briefly also spelt Kristiania). In 1925, the city reclaimed its original Norwegian name, Oslo. The diocese of Oslo is one of the five original dioceses in Norway, which originated around the year 1070.