After the Crimean War, France advocated the merger of the two principalities to prevent Russia from moving south. The Principality of Wallachia and the Principality of Moldavia were merged in 1859, and after the merger, it was called Romania, which was attached to the Ottoman Empire. And declared independence on May 9, 1877. In 1878, the region of South Bessarabia belonged to Russia. Romania was renamed the Kingdom of Romania in 1881. Moldova (Bessarabia) declared independence in January 1918 and merged with Romania in March of the same year. After the collapse of the Austro-Hungarian Empire after World War I, Romania's territory was further expanded into the regions of Valezia, Bucovina, and Bessarabia. In 1940, the Soviet Union occupied part of Romania, which became what is now Moldova (Moldavia in Latin) and a small part of Ukraine.