This ad refers to Jews of Polish & Lithuanian heritage only. The most important things is the understanding that prior to the end of WW-I, the European map was very different than the one we know today. Countries like Poland and Lithuania did not exist as independent countries, and until 1918 these territories were only known as Lithuanian or Polish regions/ counties of the Great Russian Empire who ruled all of north eastern Europe. Accordingly, until 1918, residents of these territories were Russian citizens, as Polish and Lithuanian citizenships didn’t exist. Therefore, since applications for reinstatement of these citizenships can only be based on whether one’s ancestor was a Polish or Lithuanian citizen, whoever is a descendant of an ancestor who left Europe prior to 1918 will not be eligible.
In addition, it is highly important to remember that since borders in Europe were shifted once again during and after WW-II, one’s eligibility for Polish or Lithuanian citizenship depends on the city from which his/her ancestor hailed. Horesh explains: Shifted borders resulted in cities changing nationalities, and that the resultant effect for descendants of Jews left Vilnius is that their application for Lithuanian citizenship will be declined whereas a similar application for reinstatement of Polish citizenship may very well be approved!