The territorial evolution of Romania () includes all the changes in the country's borders from its formation to the present day. The precedents of Romania as an independent state can be traced back to the 14th century, when the principalities of Moldavia and Wallachia were founded. Wallachia during its history lost several portions of its territory, either to the Ottomans or the Habsburgs. However, this land would be later essentially recovered in its entirety. Moldavia, on the other hand, suffered great territorial losses. In 1774, the Habsburgs invaded Bukovina and annexed it one year later, and in 1812, the Russian Empire took control of Bessarabia. Both territories were later exposed to powerful colonization policies. The principalities declared unification in 1859 as the Principality of Romania. This new state sought independence from the Ottoman Empire's vassalage, and in 1878, it fought a war against it alongside Russia. However, the latter would annex Southern Bessarabia, which was recovered decades before. Romania received Northern Dobruja as compensation, and would wage a war for the southern part against Bulgaria in 1913.
The now kingdom of Romania had great territorial ambitions which, once they were promised by the Entente, dragged Romania to World War I in 1916. Initially, it suffered a defeat leading to the loss of its Carpathian mountain passes and Dobruja in 1918. During this period, the union of Bessarabia with Romania was achieved. As the Central Powers weakened and pressure from the Entente (especially from France) increased, Romania reentered the war the same year. The Entente turned out to be the winner and Romania regained its lost territories after its initial defeat, as well as Bukovina and Transylvania. During this period, the country reached its maximum territorial extension, being known as Greater Romania.
However, Romania's neighbors were not satisfied with the new borders. Romania relied on regional alliances and protection from France and the United Kingdom at the west. However, soon Nazi Germany defeated France, causing great concern in the country. Since it was already apparent that the West could no longer protect Romania, the Soviet Union occupied Bessarabia, Northern Bukovina and the Hertsa region in 1940 after an ultimatum that Romania was forced to accept. The king, Carol II, was alarmed and sought the help of Germany to protect Romania's territory, but it forced the country to cede Northern Transylvania to Hungary and Southern Dobruja to Bulgaria. The king lost all his popularity, causing Ion Antonescu's rise to power. He officially joined Axis and demanded territories from Yugoslavia after its invasion, specifically Banat and the Timok Valley. This, however, never happened. In 1941, the Axis invaded the Soviet Union, allowing the recovery by Romania of its lost territories plus Transnistria, which was placed under military–civil administration. Nevertheless, this operation failed, and after the overthrow of Antonescu, Romania changed sides in 1944 and fought against the Axis, thus losing Bessarabia and Northern Bukovina once again to the Soviet Union. This made possible the recovery of Northern Transylvania by the country.
A communist government with Soviet backing was fully installed in the country in 1947. The Soviet Union had occupied several Romanian islands in the Danube Delta and the Black Sea, being this a territorial change which was made official in 1948. One of these islands was the Snake Island, which caused a dispute over the maritime borders between the now democratic Romania and Ukraine in 2009 in which Romania gained 80% of the disputed zone.
Nowadays, nationalists and other Romanian groups seek the territorial expansion of their country, especially through Bessarabia and Northern Bukovina.
Background
The Principality of Romania appeared in 1859 after the unification of the principalities of Moldavia and Wallachia. However, these countries were founded in the 14th century, and their borders changed repeatedly throughout history. Wallachia, which had obtained Dobruja during the reign of Mircea the Elder, lost the territory to the Ottomans at the end of it (around 1418). In the same period, the Ottomans annexed two ports north of the Danube, Giurgiu and Turnu Măgurele. In the middle of the 16th century, Wallachia also lost the city of Brăila. During the year 1600, Michael the Brave, ruler of Wallachia, unified the three Romanian principalities (Wallachia, Moldavia and Transylvania), although this union would be dismembered shortly after. The Austro-Turkish War that ended in 1718 was won by the Austrian Habsburg monarchy, which, among other lands, annexed Oltenia (the western part of Wallachia). However, the Treaty of Belgrade of 1739 again yielded Oltenia to Wallachia. In 1826, as a result of the Akkerman Convention, Wallachia reclaimed the three ports north of the Danube, drawing the Ottoman-Wallachian border across the Danube again.
On the other hand, there is the principality of Moldavia. It emerged as a state after the defeat of the Tatars by the King of Hungary, Louis I. The area remained under Hungarian influence and was formally established as a Hungarian fiefdom in 1347 under Dragoș. He was succeeded by Sas, who would be defeated by Bogdan I finishing the Hungarian suzerainty over Moldavia and starting its independence. It is argued, however, that for most (or all) of his reign and on its aftermath, Moldavia remained a Hungarian vassal (or Hungarian-Polish during the union of both from 1370 to 1382). The first Moldavian territorial change would take place a few years later. In 1388, Władysław II Jagiełło wanted money to wage a war against the Teutonic Order, so he asked Petru II of Moldavia for a loan (4,000 rubles). Pokuttya was used as a pledge, and it was ceded to it. This loan was probably never paid. The territory would become a place of dispute between Poland and Moldavia for the next two centuries, and was finally lost by the latter one in 1531 after the Battle of Obertyn. Meanwhile, it lost the ports of Kiliya and Bilhorod-Dnistrovskyi in 1484 to the Ottomans, followed by the annexation of the entire Moldavian coast (Budjak) by them in 1538. In 1711, due to the strategic importance of the town of Khotyn and the area around it, the Ottomans annexed it from Moldavia, settled it with Lipka Tatars and made it a sanjak (a province). Bukovina would later be invaded by the Habsburgs in 1774 and annexed one year later, undertaking a strong process of Ukrainization. Moldavia's last major territorial loss took place in 1812. The Ottomans and the Russian Empire would wage a war between 1806 and 1812, which ended with the Treaty of Bucharest that ceded to the latter Bessarabia, the eastern part of the principality. This region, just like Bukovina, suffered severe Russian colonization. Nevertheless, following the Russian defeat in the Crimean War, Moldavia recovered Southern Bessarabia in 1856.
After the devastation of the Kingdom of Hungary at Ottoman hands and its subsequent partition, Transylvania also became its own nearly independent state which included not only the geographic region of Transylvania, but also parts of Banat and the "Western Parts" (Bereg, Crișana, Maramureș, parts of Szolnok, Ung and others; sometimes collectively known as Partium). However, the principality was not led by Romanians and it was conquered by the Habsburgs in 1699.
History Formation and independence
In 1859, the principalities of Moldavia and Wallachia declared unification under a hereditary prince, in this case, Alexandru Ioan Cuza. Carol I was later elected as prince in 1866 after a referendum was approved. This new state was still an Ottoman vassal, and was not fully independent. Therefore, as "reluctant" allies, both Romania and Russia fought a war against the Ottoman Empire, which was defeated. However, in the aftermath, Russia attempted to retrieve Southern Bessarabia from Romania, which was repeatedly rejected. After a series of negotiations, Russia promised to respect Romania's territorial integrity with a treaty in 1877. This was broken just a year later, when Russian represented Romania in the Treaty of San Stefano of 1878, took Northern Dobruja and the Snake Island and offered it to Romania in exchange for Southern Bessarabia. This treaty was later revised by the Western powers in the Congress of Berlin, ending in the loss of Southern Bessarabia anyway. Thus, in 1878, Romania lost the territory but gained independence from the Ottomans and Northern Dobruja (including the Danube Delta).
During the negotiations, the Danubian island of Ada Kaleh was not discussed. Hungarian journalist Emil Lengyel declared "the island belonged to Turkey, but the peacemakers forgot about it at the Berlin Congress in 1878". According to the articles of this congress, the Danube had to be a neutral zone. Therefore, Austria-Hungary interpreted the island as being no man's land. Members of the Hungarian Parliament called for annexation of the island and contacted the Ottoman Empire to find out if they had their consent to do this, nevertheless the annexation was carried out in 1913. The island remained with Austro-Hungarian troops but also a Turkish civil administrator, a vague situation that would last for several decades. In 1881, the Kingdom of Romania was proclaimed.
The First Balkan War at the beginning of the 20th century presented an imbalance of the power in the region, as Austria-Hungary supported a powerful Bulgarian state and a weak and devastated Serbia. Romania did not support this, and after unfruitful negotiations, Romania joined the Second Balkan War in 1913 against Bulgaria. Ending in its victory, Romania gained Southern Dobruja, including Silistra, which was promised in 1878.
World War I
When World War I began in 1914, Romania initially maintained a policy of neutrality. However, after secret negotiations with the Triple Entente, the Treaty of Bucharest of 1916 was signed. This treaty promised Romania the regions of Transylvania, Bukovina, Banat and other Hungarian territories along the Tisza River (Crișana). Prime Minister Ion I. C. Brătianu, in charge of the Romanian foreign policy after Carol I's death in 1914, was highly suspicious of whether the Entente would deliver on its promises due to the event of Southern Bessarabia decades earlier. Therefore, he insisted on various clauses and conditions in the treaty to ensure that it would be fulfilled.
In August 1916, Romania entered the war and invaded Transylvania, but an attack by the Central Powers from the south ruined its actions. The Romanian army was courageous and enthusiastic, but it was poorly equipped and inexperienced. In December, the Central Powers had already occupied Wallachia and Dobruja. This raised doubts for the Entente as to whether Romanian claims had to be accomplished, and they did not invite Romania to participate in following conferences about the war. This changed after a visit to Moscow from Brătianu complaining about this and in which he convinced the Entente of the importance of Romania in the region. Eventually, the Russian army collapsed and Russia would be forced to abandon the war. Romania, although it had managed to repudiate an offensive towards Moldavia, was left alone on the Eastern Front and was now worried about the threat of the Russian revolutionary forces. Thus, it signed the Armistice of Focșani with the Central Powers on 9 December 1917. Meanwhile, Bessarabia, which had declared itself as the Moldavian Democratic Republic on 15 December, united with Romania on 9 April 1918. This was ratified by King Ferdinand I on 17 April.