I have browsed through the Theisen genealogy forum. To me it is surprising to see that none of the Theisens in the US seem to have Norwegian ancestors. In my family the first-name Theis has been in use since the year 1600. The family has its origin in the district Spind, close to the small town Farsund on the south coast of Norway. All my ancestors were seemen, and presumably brought the fist name Theis with them from Denmark, Germany or the Netherlands (where the name is common), perhaps through marrying a woman from one of those countries. To me it is rather strange to learn that people with the family name Theisen have emigrated to the US from Luxenbourg or Germany. The reason is that the family name Theisen has a typical Norwegian/Danish form, and means the son of Theis. To my knowledge, the format of family names in the Netherlands, Luxembourg and Germany are different. One possiblility could be that some people carrying the name Theisen have moved from Norway to another European country, and from there later moved to the US. Since there were close connections between the countries around the North Sea this is quite likely. Another possibility is that some Theisens have moved directly from Norway to the US. People in the area where my ancestors come from were very poor, and a lot ot people from the south coast of Norway therefore moved to the US.