The Day of the Union of Bessarabia with Romania (Romanian: Ziua Unirii Basarabiei cu România) is a public holiday of Romania celebrated every 27 March to commemorate the union of Bessarabia with Romania on 27 March 1918. Bessarabia is a Romanian historical region that was part of the Principality of Moldavia, which united with Wallachia to form modern Romania. The region was annexed in 1812 by the Russian Empire, but it became independent and united with Romania on 27 March 1918.