Das polnische Volk im 19. Jahrhundert

Note that just the darkest shade depicts Polish majority, other shades show minorities of >30%, >20%, >10%, >5%, >3% and >1%.

I believe this is late 19th century. Polish language was rapidly shrinking during the 19th century and reached much further west around 1801. Even Wrocław/Breslau was still bilingual with the northern half of the city being called “Polish side”.

Yes, the decline of Polish was due to massive measures by the Prussian state. In fact if it happened today, it would be called cultural genocide.

This is getting silly. Not only are Masurians here marked as Polish, when they very obviously didn’t consider themselves so, but now we have Belarusian speakers in places like Latgale marked as Poles because “religion correlates with ethnicity better than language? Even though said population at no point had Polish self-identity and declared themselves Belarusians in both post-WW1 Latvian censuses AND current censuses?

Methodology?

The Pole of Settlement