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.