Hallmarks have been used in Norway since the Sixteenth Century. The system included, at various times and in various combinations; city marks, assayer's marks, date letters, date numbers, and maker's marks. The farther a piece was made from the main population centers of Oslo (Christiana), Bergen and Trondheim, the more likely there were to be mark inconsistencies. The bureaucracy in control of silver marking seesawed between the Crown and the Silver Guilds for a few centuries and finally, in 1891, a simplified national system was established that is still in use.

The current system requires only a silver standard mark and maker's mark. The old Norwegian standard of .830 purity silver is still used, but beginning around 1920, .925 purity began replacing it and is now the foremost standard in use. Town names are sometimes included with the required marks and the letters "NM" (Norsk Mønster) are sometimes seen on flatware, they are an indication of patent or copyright.
Below are illustrations of many of the latter 19th and 20th century silver producers of Norway. I will add to it as I find or am sent mark illustrations.

Magnus Aase
Bergen 1876-1953

Andresen & Scheinpflug
Oslo

Øystein Balle
Stavinger

David-Andersen
Oslo

DAVID-ANDERSEN
The company was founded in Christiania (now Oslo), Norway by David Andersen in 1876. Andersen (1843-1901) was a gold and silversmith with a keen sense of quality and the high standards of his workmanship brought early success. By 1888, Andersen was able to expand his workshop into a steam powered plant and a second retail location was opened in Oslo in 1892. David Andersen died in 1901 and his son, Arthur Andersen, took the reins of the firm. Arthur instituted some important changes, he decided to hyphenate the family name to David-Andersen, and as chief designer, he introduced the use of enameling on the company's gold and silver jewelry and holloware. The new line was so successful that enamelled jewelry has become nearly synonymous with the David-Andersen name. The firm has always remained a family business and is now run by members of the fourth generation, Uni and Jon David-Andersen.

The company has kept pace with changing times and artistic trends, they have produced beautiful and finely crafted jewelry and objects in the styles of; Naturalism, Dragestil (Dragonstyle), Art Nouveau, Art Deco, Art Moderne, and Modernism. A few of their early designers include:

Arthur David-Andersen (1875•1970)
Johan Lund (active 1890's)
Gustav Guadernack (1865•1914)
Guttorm Gagnes (1906•1964)
Ivar David-Andersen (1903•1998)
Thorbjørn Lie-Jørgensen (1900•1961)

Elvik & Co. A/S
Oslo

Marius Hammer
Bergen 1847-1927

Kristian M. Hestenes
Bergen

Nils Hansen - Oslo Sølvvareverksted
Ørje 1926 - 1990

Aksel Holmsen
Sandefjord

Ivar Holth
Oslo

A. Holthe A/S
Arendal

Ottar Hval
Oslo

Frank & Regine Juhls
Kautokeino

Brødrene Lohne
Bergen

Thorvald Marthinsen
Tonsberg

Bernard Meldah
Oslo

Einar Modahl
Oslo

Henrik Møller
Trondheim, 1858-?

Brødrene Mylius
Kragerø

Theodor Olsens Eftf
Bergen

Hroar Prydz
Oslo

Albert Scharning
Oslo
There is also a script version of this mark.

N. M. Thune
Oslo

J. Tostrup
Oslo