The holiday was first proposed in 2015 by the Romanian politician Titus Corlățean[1] and subsequently promulgated on 18 November 2020 by President Klaus Iohannis.

[4][5] It has been claimed that the Romanian decision for promulgating the holiday was because of the earlier establishment of 4 June in Hungary as the "Day of National Unity" and to endorse anti-Hungarian sentiments.

[1] On the other hand, Corlățean, who proposed the law passed by the Parliament of Romania, declared to BBC News: "I do not understand why the Romanians should be shy of marking what was fundamental for their history, because we don't want to offend anyone".

As a result, Transylvania, as well as parts of Banat, Crișana and Maramureș, were officially allocated to Romania.

Hungary also lost territories to Austria, Czechoslovakia, the Kingdom of Serbs, Croats and Slovenes and Poland as a consequence of it.