Finland:
It gained its independence from Russia.
Estonia:
It was established as a separate nation after the breakup of the Russian Empire.
Latvia:
Like Estonia, Latvia also emerged from the Russian Empire and became an independent state.
Lithuania:
It regained independence after being under Russian control.
Poland:
Poland was re-established as an independent nation after more than a century of being partitioned among Russia, Prussia, and Austria.
Czechoslovakia:
Created from parts of the former Austro-Hungarian Empire, it included the Czech lands, Slovakia, and Ruthenia (now part of Ukraine).
Yugoslavia:
Formed from the unification of several South Slavic territories, including Serbia, Croatia, Slovenia, Bosnia and Herzegovina, and parts of Macedonia and Montenegro.
Austria:
It was established as a separate country following the dissolution of the Austro-Hungarian Empire.
Hungary:
Hungary also came into existence as an independent state after the collapse of the Austro-Hungarian Empire.