Oslo is the capital and most populous city of Norway. It constitutes both a county and a municipality. Founded in the year 1040, and established as a kaupstad or trading place in 1048 by Harald Hardrada, the city was elevated to a bishopric in 1070 and a capital under Haakon V of Norway around 1300. Personal unions with Denmark from 1397 to 1523 and again from 1536 to 1814 and with Sweden from 1814 to 1905 reduced its influence. After being destroyed by a fire in 1624, during the reign of King Christian IV, a new city was built closer to Akershus Fortress and named Christiania in the king's honour. It was established as a municipality (formannskapsdistrikt) on 1 January 1838. The city's name was spelled Kristiania from 1877 and 1897 by state and municipal authorities, respectively. In 1925 it was renamed Oslo.