Originally Posted by
rothaer
Maybe it has to be said that Friesland does not automatically mean Frisians. Ethnic Frisians live in Frisland in the Netherlands, also called West Frisia, and in North Frisland, which is in NW Schleswig-Holstein. But Frisians are there just a minority, also in the Islands. So if you have an indigenous individual from an Island in North Frisia, the probabillity that it is a non_Frisian is high. They might be Saxons or other Germans or one or another also a Dane. The individual could be used for Schleswig-Holstein if the pedigree supports it farther back.
Btw. there is also Ostfriesland (East Frisland) in Lower Saxony that is bordering the Frisland in Netherlands. But these "Ostfriesen" and their language (ostfriesisch) are actually not Frisian. They are Germanised and the ancestry proportion of Frisians is not known to me.