Christopher Hansteen (26 September 1784 – 11 April 1873) was a Norwegian geophysicist, astronomer and physicist, best known for his mapping of Earth's magnetic field. Early life and career Hansteen was born in Christiania as the son of Johannes Mathias Hansteen (1744–1792) and his wife Anne Cathrine Treschow (1754–1829). He was the younger brother of writer Conradine Birgitte Dunker, and through her the uncle of Bernhard Dunker and Vilhelmine Ullmann, and granduncle of Mathilde Schjøtt, Ragna Nielsen and Viggo Ullmann. His mother was a first cousin of Niels Treschow. The intention was for Hansteen to become a naval officer, but since his father died when Hansteen was young, this plan did not materialize. Instead, he attended Oslo Cathedral School from the age of nine. Niels Treschow was the principal of this school. Hansteen took the examen artium in 1802, and in 1803 he enrolled at the University of Copenhagen, where he originally studied law. He later took more interest in mathematics, estranged by the lack of universal validity of a country's laws compared to the mathematical laws. He had also been inspired by the lectures of Hans Christian Ørsted. He was hired as the tutor of a young noble, Niels Rosenkrantz von Holstein, who lived at Sorø. Here, he also met his future wife Johanne Cathrine Andrea Borch, a daughter of professor Caspar Abraham Borch. In 1806 he was hired as a mathematics teacher in the gymnasium of Frederiksborg. Academic career In 1807 Hansteen began the inquiries in terrestrial magnetism with which his name is especially associated. His first scientific publication was printed in Journal de Physique, following a contest on magnetic axes created in 1811 by the Royal Danish Academy of Sciences and Letters. In 1813 he was given a research scholarship by the recently established (in 1811) Royal Frederick University in Christiania, with a promise of a future academic position. After marrying Johanne Cathrine Andrea Borch in May 1814, they left for Norway in the summer. Due to the Swedish campaign against Norway in 1814, they opted to travel by sea, and was threatened by a Swedish privateer as well as seized by a British fregate en route. Reaching Norway after five days, they settled in the street Pilestredet. Working as a lecturer from 1814, in 1816 Hansteen was promoted to professor of astronomy and applied mathematics. He was the editor of the official Norwegian almanac from 1815,