Reconstruction and anniversary of the event will take place on 20.05.2019 (Monday) near Freedom's street (ulica Wolności) in Bytów:

http://www.kaszuby.pl/Rekonstrukcja_...QQid,1046.html

"(...) March of Kashubians on Bytów was an act of protest against the provisions of the Treaty of Versailles. During the Paris Peace Conference of 1919 which reshaped the world after WW1 and delineated new borders, most of the territory of Bytów County (Kreis Bütow) became part of Weimar Germany. A large part of several thousand Kashubians living in that county protested against that situation. On 16 May 1920, when the International Border-Delineation Commission was visiting Bytów, several hundred Kashubians from Niezabyszewo (Damsdorff) and Ugoszcz (Bernsdorf) parishes - led by Bernard Werra, Jan Styp-Rekowski and Antoni Schroeder - came to Bytów during the so called 'march on Bytów' and delivered a declaration of their protest against leaving them within the borders of Germany."

=====

Edit:

In the whole county about 20% or a bit more were Kashubians, and in south-eastern part of it - the majority:

https://www.academia.edu/28767886/_M...016_s._280-310

This map below is based on official German census of 1910 (green = Polish/Kashubian-speaking majority):



Maybe the census underestimated the number of Kashubian-identified people in some of "orange" villages?

Most of these villages have names of Slavic origin even in orange area (= German-speaking majority in 1910).