During the final months of World War I, Polish and Czechoslovak diplomats met to discuss the common border between the two new countries.

[6] Latin, German, Czech, Moravian and finally Polish served as an official language of the region, however throughout the ages many historical sources indicate the local population remained mostly or overwhelmingly Polish-speaking, with everyday speech being Cieszyn Silesian dialect, regardless of the official language governing, even after the settlement of Czechs, in large part professionals, white-collars workers during the 19th century industrialization of the region.

[7] The region had hosted no local Czech independence organizations, but had been the site of a Polish association since the early 19th century, and had been the site of a branch of the Polish Social Democratic Party of Galicia and Cieszyn Silesia, mentioned in its full name, which had been the most popular party in the region.

The last Austrian census of 1910 (determining nationality according to the main communication language (German: Umgangssprache) of the respondents), showed that it was predominantly Polish-speaking in three districts (Cieszyn (Teschen), Bielsko (Bielitz), and Fryštát (Freistadt)) and mainly Czech-speaking in the fourth district of Frýdek (Friedek).

[10] The chief importance of Cieszyn Silesia was the rich coal basin around Karviná and the valuable Košice-Bohumín Railway line which linked the Czech lands with Slovakia.

Furthermore, in the north-western part of Cieszyn Silesia, the railroad junction of Bohumín served as a crossroad for international transport and communications.

The operations of the Czechoslovak forces were joined by other local volunteers, formed in the National Guard approximately 5,000 men strong.

During the war the Czechoslovak army was reinforced by the newly formed 2nd Brigade with a strength of six battalions, with the support of two artillery batteries, and one cavalry squadron.

On 30 January 1919 Josef Šnejdárek received the order to cross the Vistula and secure the railway line between Bohumín and Jablunkov/Jabłonków.

On 31 January 1919, because of the pressure from the Triple Entente representatives, the attack on Skoczów was cancelled, and the Czechoslovak army ceased fighting.

The Czechoslovak army withdrew to the new Green Line, established by the International Commission Agreement on the basis of the Czechoslovak–Polish Treaty, concluded on 3 February 1919 in Paris.

Vast majority of the coal mines, as well as Třinec Iron and Steel Works were on the territory assigned to Czechoslovakia.

[20] Several thousand people were forced to flee to Poland, who returned in 1938 with the Polish annexation of Trans-Olza and in turn started taking revenge on the local Czech populace.