Really a specialised field
Once Denmark extended southwards to the boundaries of HAMBURG the HANSA trading town on the river ELBE which a Danish King tried to capture - but it was a too tough nut for him to crack.
PRUSSIA was an independant state much of which is POLAND today.
ALTONA was Danish from 1640 to 1864 and an independant town until 1937.
An attempt to separate the Duchy of Holstein from Denmark led to the Danish Pussian war of 1848 to 1850
The next war in 1864 meant SCHLESVIG and HOLSTEIN were lost to Prussian and Austria
In 1920 SLESVIG the northern half of SÃ˜NDERJYLLANDS amt was returned to Denmark after a referendum.
also spelled SCHLESWIGhttp://www.google.com/search?num=100&hl=en&lr=&i...
a handy map http://feefhs.org/maps/gerw/gw-schl.html
note ANGELN peninsular where the ANGLO SAXON tribes came from.
The islands may be called FRIESIAN also SYLT
the Freisians being sailors and traders and mercenary soldiers some of whom settled in Wales about 1080http://images.google.com/images?hl=en&lr=&ie=ISO-885...
lots of horses toohttp://images.google.com/images?hl=en&lr=&ie=ISO-885...
For genealogists there are german families living in Denmark and Danes living in Saxony
The boundaries are political not culturalhttp://ddd.dda.dk/
the absent census from 1870 shows when they were Germans
double clicking nysquae produces a mpa showing parishes
Sydslevig in 1860http://www.dis-danmark.dk/kipkort/kort/hols1860.gif
shows HAMBURG and LÃœBECK retaining their independance as city states
better stop there
the -sen names are the most common Danish patrynomics
I will try and findd some German statistics
You get German families all over Denmark
SCH is a give away eg former prime Minister POUL SCHLÃœTER
Czech too REINCKE via POMMERN now in POLAND