Fridtjof Nansen particularly in the polar regions. The Nansen family originated in Denmark. Hans Nansen (1598–1667), a trader, was an early explorer of the White Sea region of the Arctic Ocean. In later life he settled in Copenhagen, becoming the city's "borgmester" in 1654. Later generations of the family lived in Copenhagen until the mid-18th century, when Ancher Antoni Nansen moved to Norway (then in a union with Denmark). His son, Hans Leierdahl Nansen (1764–1821), was a magistrate first in the Trondheim district, later in Jæren. After Norway's separation from Denmark in 1814, he entered national political life as the representative for
Fridtjof Nansen like a spiral staircase, down towards the depths". In 1909 Nansen combined with Bjørn Helland-Hansen to publish an academic paper, "The Norwegian Sea: its Physical Oceanography", based on the "Michael Sars" voyage of 1900. Nansen had by now retired from polar exploration, the decisive step being his release of "Fram" to fellow Norwegian Roald Amundsen, who was planning a North Pole expedition. When Amundsen made his controversial change of plan and set out for the South Pole, Nansen stood by him. Between 1910 and 1914, Nansen participated in several oceanographic voyages. In 1910, aboard the Norwegian naval vessel "Fridtjof", he