Oslo is the capital and the most populous city in Norway. After being destroyed by a fire in 1624, the city was moved closer to Akershus Fortress during the reign of King Christian IV and renamed Christiania in his honour. It was established as a municipality (formannskapsdistrikt) on 1 January 1838. Following a spelling reform, it was known as Kristiania from 1877 to 1925, at which time its original Norwegian name was restored.

Oslo is the economic and governmental centre of Norway. The city is also a hub of Norwegian trade, banking, industry and shipping. It is an important centre for maritime industries and maritime trade in Europe. The city is home to many companies within the maritime sector, some of which are among the world's largest shipping companies, shipbrokers and maritime insurance brokers. Oslo is a pilot city of the Council of Europe and the European Commission intercultural cities programme.

Oslo is considered a global city and ranked "Beta World City" in studies carried out by the Globalization and World Cities Study Group and Network in 2008. It was ranked number one in terms of quality of life among European large cities in the European Cities of the Future 2012 report by fDi magazine. In 2013 Oslo tied with the Australian city of Melbourne as the fourth most expensive city in the world, according to the Economist Intelligence Unit (EIU)'s Worldwide Cost of Living study [Wikipedia.org]