Greater Romania The Greater Romania ( ) generally refers to the territory of Romania in the years between the First World War and the Second World War , the largest geographical extent of Romania up to that time and its largest peacetime extent ever ( 295 , 049 km² ) ; more precisely , it refers to the territory of the Kingdom of Romania between 1919 and 1940 . In 1918 , at the end of World War I , Transylvania , Bukovina and Bessarabia united with the Romanian Old Kingdom . Union of Bessarabia with Romania . Bessarabia , having declared its sovereignty as Moldavian Democratic Republic in 1917 by the newly formed " Council of the Country " ( " Sfatul Ţării " ) , was faced with the disorderly retreat of disbanded Russia n troops through its territory . In January 1918 , Sfatul Ţării called on Romanian troops to protect the province from the Bolsheviks who were spreading the Russian Revolution . After declaring independence from Russia on 24 January 1918 , " Sfatul Ţării " voted for Union with Romania on 9 April 1918 : of the 138 deputies , 86 voted for union , 3 against , 36 abstained ( mostly the deputies representing the minorities , 36 % at the time ) and 13 were not present . Union of Transylvania with Romania . Transylvania ( the last of the three to do so ) joined Romania by a " Proclamation of Union " of Alba Iulia adopted by the Deputies of the Romanians from Transylvania , and supported one month later by the vote of the Deputies of the Saxons from Transylvania . The Hungarian - speakers from Transylvania , about 32 % at the time ( including a large Hungarian - speaking Jewish community ) , and the Germans in Banat did not elect Deputies at the official dissolution of Austro - Hungary , since they were considered represented by the Budapest government of the Hungarian part of the Austro - Hungary . Bukovina . In Bukovina , after occupation by the Romanian Army , a National Council voted for union with Romania . While the Romanian , German , and Polish deputies unanimously voted for union , the Ukrainian deputies ( representing 38 % of the population according to the 1910 Austrian census ) and Jewish deputies did not attend . International treaties . The union of the regions of Transylvania , Maramureş , Crişana and Banat with the Old Kingdom of Romania was ratified in 1920 by the Treaty of Trianon which recognised Romanian sovereignty over these regions and settled the border between the independent Republic of Hungary and the Kingdom of Romania . The union of Bukovina and Bessarabia with Romania was ratified in 1920 by the Treaty of Versailles . Romania had also recently acquired the Southern Dobruja territory called the " Cadrilater " ( " Quadrilateral " ) from Bulgaria as a result of its victory in the Second Balkan War in 1913 . Interwar period . Romania retained these borders from 1918 to 1940 . That year , it lost Bessarabia to the Soviet Union , as provided for by the Molotov - Ribbentrop pact . Additionally , it also lost the Northern Bukovina and the Herţa region to the Soviet Union ( not mentioned in the pact ) , as well as Northern Transylvania to Hungary , due to the Second Vienna Award , and the " Cadrilater " to Bulgaria in the Treaty of Craiova . In the course of World War II , Romania ( in alliance with the Axis Powers ) took back Bessarabia and was awarded further territorial gains at the expense of the Soviet Union ( Transnistria / western Yedisan / western New Russia ) ; these were lost again as the tide of the war turned . After the war , Romania regained the Transylvanian territories lost to Hungary , but not those lost to either Bulgaria or the Soviet Union , and in 1948 the Treaty between the Soviet Union and Soviet - occupied Communist Romania also provided for the transfer of four uninhabited islands to the USSR , three in the Danube Delta , and one in the Black Sea ( Snake Island ) . Name . The original Romanian term , " " România Mare " , " or " Great Romania " , carried irredentist overtones , used in the sense of " re - integration " of the territories that shared Romanian language and culture . The term became more common after the Treaty of Versailles , when the attachment of Transylvania to the Kingdom of Romania occurred as a result of the Treaty of Trianon ; thus the Kingdom of Romania under King Ferdinand I came to include all provinces with an ethnic Romanian majority , by comparison with the previous Romanian Old Kingdom under King Carol I , which did not include the provinces of Transylvania , Bessarabia and Bukovina . An alternative name for " România Mare " , coined at the same time , was in the Romanian language " România Întregită " ( roughly translated in English as " Romania Made Whole , " or " " Entire Romania " " ) . " România Mare " was seen ( and is also now seen by the great majority of the Romanian people , both at home and abroad ) as the ' true ' , " whole " Romanian state , or , as Tom Gallagher states , the " Holy Grail of Romanian nationalism " . When used in a political context it has an irredentist connotation , mainly concerning the territories that were ruled by Romania in the interwar , that are now part of Ukraine , the Republic of Moldova or Bulgaria .