estimated that in the period 1914–1918 between 400,000 and 600,000 soldiers of Romanian origin fought on different fronts of Austria-Hungary, which represented a significant percentage of the Romanian ethnics who lived in those times in the Empire. In total, up to 150,000 Romanians were killed in action while fighting as part of the Austro-Hungarian Army. Greater Romania (1918–1940) Before World War I, the union of Michael the Brave, who ruled over the three principalities with Romanian population (Wallachia, Transylvania and Moldavia) for a short period of time, was viewed in later periods as the precursor of a modern Romania, a thesis which was argued with noted intensity by Nicolae Bălcescu. This theory became a point of reference for nationalists, as well as a catalyst for various Romanian forces to achieve a single Romanian state. The Romanian revolution in 1848 already carried the seeds of the national dream of a unified and united Romania, though the "idea of unification" had been known from earlier works of Naum Ramniceanu (1802) and Ion Budai-Deleanu (1804). The concept owes its life to Dimitrie Brătianu, who introduced the term "Greater Romania" in 1852. The first step in unifying Romanians was to establish the United Principalities by uniting Moldavia and Wallachia in 1859, which became known as Romania since the 1866 Constitution and turned into a Kingdom in 1881, after gaining independence from the Ottoman Empire. However, before the Austro-Hungarian Compromise, the elite of the Transylvanian Romanians did not support the concept of "Greater Romania", instead they wanted only equality with the other nations in Transylvania. The concept became a political reality when, in 1881, the Romanian National Party of Transylvania gathered Romanians on a common political platform to fight together for Transylvania's autonomy. According to Livezeanu the creation of Greater Romania with "a unifying concept of nationhood" started to evolve in the late 1910s. World War I played a crucial part in the development of Romanian national consciousness. In 1918, at the end of World War I, the union of Romania with Bukovina was ratified in 1919 in the Treaty of Saint Germain, and some of the Allies recognized the union with Bessarabia in 1920 through the never ratified Treaty of Paris. On 1 December, the Deputies of the Romanians from Transylvania voted to unite Transylvania, Banat, Crișana and Maramureș with Romania by the Proclamation of Union of Alba Iulia. Romanians today celebrate this as