1918 unification of the Kingdom of Romania with the region of Transylvania
The union of Transylvania with Romania was declared on 1 December [O.S. 18 November] 1918 by the assembly of the delegates of ethnic Romanians held in Alba Iulia. The Great Union Day (also called Unification Day[1]), celebrated on 1 December, is a national holiday in Romania that celebrates this event. The holiday was established after the Romanian Revolution, and celebrates the unification not only of Transylvania, but also of Bessarabia and Bukovina and parts of Banat, Crișana and Maramureș with the Romanian Kingdom. Bessarabia and Bukovina had joined with the Kingdom of Romania earlier in 1918.