Harald V of the House of Glücksburg is the current King of Norway. Erna Solberg has been prime minister since 2013 when she replaced Jens Stoltenberg. As a unitary sovereign state with a constitutional monarchy, Norway divides state power between the parliament, the cabinet and the supreme court, as determined by the 1814 constitution. The kingdom was established in 872 as a merger of many petty kingdoms and has existed continuously for 1, years. From 1537 to 1814, Norway was a part of the Kingdom of Denmark–Norway, and from 1814 to 1905, it was in a personal union with the Kingdom of Sweden. Norway was neutral during the First World War and remained so until April 1940 when the country was invaded and occupied by Germany until the end of World War II.