{{Short description|Norwegian archivist}} '''Jens Jonas Schroeter Jansen''' (19 September 1900 – 26 October 1975) was a Norwegian archivist.
He was born in Bærum as a son of vicar Jens Jonas Elstrand Jansen (1844–1912) and Jenny Therese Schroeter (1863–1942), and brother of Einar Jansen. In 1937 he married Hjørdis Sofie Berg.<ref name=hvem/>
He finished his secondary education in 1918 and graduated from the Royal Frederick University with the cand.philol. degree in 1927<ref name=hvem>{{cite encyclopedia|year=1973|title=Jansen, Jonas|encyclopedia=Hvem er hvem?|editor=Steenstrup, Bjørn|publisher=Aschehoug|location=Oslo|url=https://runeberg.org/hvemerhvem/1973/0280.html|page=280|language=Norwegian|access-date=9 May 2012}}</ref> with a master's thesis on the Treaty of Björkö.<ref name=70y>{{cite news|title=Jonas Jansen fyller 70 år|date=19 September 1970|work=Aftenposten|page=10|language=Norwegian}}</ref>
He worked in the National Archives of Norway from 1936 to 1956, and also worked as a consultant in the Ministry of Foreign Affairs from 1949 to 1952. He was then the manager of Norsk Historisk Kjeldeskrift-Institutt from 1953 to 1970. He is also known as a co-editor of the biographical dictionary ''Norsk Biografisk Leksikon'' from 1954. He chaired the union Arkivarforeningen from 1938 to 1947 and was a board member of Kjeldeskriftfondet from 1940 to 1945 and of the Norwegian Genealogical Society from 1949.<ref name=hvem/>
In private relations, he used the very conservative pre-1907 orthography.<ref name=70y/> He died in 1975.<ref name=obit>{{cite news|title=Instituttsjef Jonas Jansen|date=29 October 1975|work=Aftenposten|page=19|author=Mannsåker, Dagfinn|authorlink=Dagfinn Mannsåker|language=Norwegian}}</ref>
==References== {{Reflist}}
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{{DEFAULTSORT:Jansen, Jonas}} Category:1900 births Category:1975 deaths Category:People from Bærum Category:University of Oslo alumni Category:Norwegian archivists Category:Norwegian encyclopedists Category:20th-century Norwegian writers Category:20th-century Norwegian trade unionists Category:20th-century archivists
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