History of Transylvania union of Transylvania with Romania in Alba Iulia on 1. December 1918.; Bessarabia, having declared independence from Russia in 1917 at the Conference of the Country (Sfatul Țării), called in Romanian troops to protect the province from the Bolsheviks. The union of the Transylvania, Maramureș, Crișana and Banat regions with the Old Kingdom of Romania was ratified in 1920 by the Treaty of Trianon, which recognised the sovereignty of Romania over these regions and settled the border between the Republic of Hungary and the Kingdom of Romania. The union of Bukovina and Bessarabia with Romania was ratified in 1920 by
Principality of Transylvania (1570–1711) West and north Royal Hungary, Ottoman Hungary, and the Eastern Hungarian Kingdom under Ottoman suzerainty, which later became the Principality of Transylvania where Austrian and Turkish influences vied for supremacy for nearly two centuries. The Hungarian magnates of Transylvania resorted to policy of duplicity in order to preserve independence. Transylvania was administrated by Isabella, John Sigismund's mother from 1541 to 1551, when it fell for 5 years (1551–1556) under Habsburg rule. The House of Zapolya gained again the control of Transylvania in 1556, when the Diet of Szászsebes elected Sigismund as prince of Transylvania. Transylvania was now beyond the reach