Oscar Albert Johnsen was a Norwegian historian. He published a number of books on historical topics.
Life
Johnsen became a student a 1896; he graduated with a master's degree in 1898, and in 1906 he received a PhD with his dissertation De norske stænder. In 1906 and 1907 he studied as a government scholar in Copenhagen, Paris, and Berlin. Later, he made a number of study trips abroad, including to England, Germany, and the Baltic countries. He was professor of history at the University of Oslo from 1913 to 1945. Johnsen and Halvdan Koht influenced Norwegian historiography in the 1900s through their views that there was no constitutional equality between Denmark and Norway after the introduction of the absolute monarchy in AD 1660. Together with the teachers Lorens Berg from Andebu and Jacob Aaland from Nordfjord, as well as Edvard Bull Sr., Johnsen was central to the new local historical movement that arose after the dissolution of the union. This led to the establishment of the National Society for Rural and Urban History in 1920, where Johnsen served as chairman from the its beginning until 1945. Johnsen, Berg, and Aaland worked closely together and set the standard for the modern local history book. They orientated themselves beyond the discipline of history and studied life in a small community based on source-critical studies in local and national archives. During the Second World War, the nationally conservative Johnsen was head of the newly created Institute for Medieval Texts. The institute did not receive any special support from the Germans, but the Nasjonal Samling party was very interested in it. Johnsen was accused of cooperating too strongly with the Nazi ministry. Johnsen was the editor of the journal Heimen from 1922 to 1945 and the editor of the local history yearbook Vestfoldminne from 1924 to 1932. He was a recipient of the Swedish Order of the Polar Star. In 1901 Johnson married Anna Evie Tollefsen, the daughter of Even Tollefsen, the inventor of the tanker. They had four children, the youngest of whom was the historian Arne Odd Johnsen.
Books
Hurum herred – en historisk-topografisk beskrivelse
Bohuslens eiendomsforhold – indtil omkring freden i Roskilde
De norske stænder. Bidrag til oplysning om folkets deltagelse i statsanliggender fra reformationen til enevældet
Lærebok i Norges, Danmarks og Sveriges historie for gymnasiene
Hannibal Sehesteds statholderskab 1642-1651 – et tidsskifte i Norges historie
Soga um Norig, Sverike og Danmark
Norges bønder – utsyn over den norske bondestands historie
Larviks historie
Finmarkens politiske historie
Noregsveldets undergang
Tønsbergs historie
Rapports de la Légation de France a Copenhague – Relatifs a la Norvége 1670–1791, Tome 1, 1670–1748
Innføring i kildene til Norges historie inntil det 19. århundre
Norwegische Wirtschaftsgeschichte
Norges brannkasse 1767-1942
Sem og Slagen – en bygdebok
Tønsbergs sparebank gjennem hundre år – 1847–1947
Articles
"Bidrag til Oplysning om Befolkningsforholdene og Almuens økonomiske Stilling i Bohuslen før Afstaaelsen " Historisk tidsskrift 1905 18: 187–247
"Et aktstykke fra stænderforhandlingerne i Kristiania 1645" Historisk tidsskrift 1907 19: 81–97
"Raad mod Borgerskab. Kristiania-Interiør fra Midten af det 17de Aarhundre" Historisk tidsskrift 1909 20: 532–559
"Om det norske folks opfatning av tronfølgen før 1660" Historisk tidsskrift 1914 23: 190–221
"Snorre Sturlasons opfatning av vor ældre historie" Historisk tidsskrift 1916 24: 213–232
"Fridgerdar-saga. En kildekritisk undersøkelse" Historisk tidsskrift 1916 24: 513–539
"Sarpsborgs gamle kirker" Historisk tidsskrift 1916 24: 540–545
"Om haandskriftene til den store Olav den helliges saga" Historisk tidsskrift 1920 25: 382–401
"Gjensidige nationale stemninger hos nordmænd og svensker, særlig i det 16. og 17. aarhundred" Historisk tidsskrift 1924 26: 233–261
"Gildevæsenet i Norge i middelalderen. Oprindelse og utvikling" Historisk tidsskrift 1924 26: 73–101
"Nordiske handelsforbindelser med Frankrike før 1814" Historisk tidsskrift 1927–29 28: 268–298
"Kilder i utenlandske samlinger til norsk handels- og sjøfartshistorie i nyere tid " Historisk tidsskrift 1927–29 28: 491–505
"Norges handel på Spania under Kristian IV" Historisk tidsskrift 1930–33 29: 225–240
"Nederland og Norge 1625-1650. Gjensvar til dr. Johan Schreiner" Historisk tidsskrift 1934–36 30: 479–487