04 June 1920
The Treaty of Trianon demarcated the southern border of Slovakia. This border was decided in the most complicated way. In the area with a mixed population, it was decided not only according to the accepted right of self-determination, but also according to economic and military-strategic factors. Hungarian efforts to revise it and defend against anti-revisionism became a key policy component of both countries in the coming decades.Handing-over twenty-five villages to Poland became a problem for Slovak borders in the north.