The black plague (Svartedauen) was brought to Bergen by passengers of a ship in the late summer of 1349. It wiped out the majority of the Norwegian noble class, as well as approximately one-half to two-thirds of the rest of the population. As the black plague concluded, members of the Danish ruling class became the dominate force for governing a united Norway and Denmark. Most Norwegian nobility after this time is of Danish origin. An 1849 amendment to the Norwegian constitution, written in 1814, abolished all nobility.
Although some original records such as the grant of nobility still exist, you can adequately accomplish most nobility research in secondary sources. These include published or manuscript genealogies of noble families.
An important source for Norwegian nobility research is:
Danmarks Adels Arbok (Danish Nobility Yearbook). København. First volume published in 1884. Some of the latest issues are not on microfilm. (FHL book 948.9 D55d; film 1124534-45)
Norsk Slektshistorisk Tidsskrift (Periodical of Norwegian Family History) This also has many articles about Norwegian noble families. See the "Periodicals," "Societies" and "Genealogy" sections for more information.
I balansepunktet (In the balance point) includes many nobility families for several generations, mainly from the region of Sunnmøre, Møre og Romsdal, Norway. It also includes some nobility families from the west coast of Norway. This book covers the time frame from about 800 to 1700 (FHL book 948.35 H2u)
The Family History Library has collected other records of noble families. These records are listed in the catalog under:
NORWAY - NOBILITY
NORWAY, [COUNTY] - NOBILITY
NORWAY, [COUNTY], [TOWN] - NOBILITY